xtensa: fixup simdisk driver to work with immutable bio_vecs

Geert reported:

arch/xtensa/platforms/iss/simdisk.c:108:23: error: 'struct bio' has no member named 'bi_sector'
arch/xtensa/platforms/iss/simdisk.c:110:2: error: incompatible types when assigning to type 'int' from type 'struct bvec_iter'
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_size' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_size' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_size' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_bvec_done' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_bvec_done' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bi_bvec_done' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:110:2: error: request for member 'bv_len' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_size' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_size' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_bvec_done' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_bvec_done' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_bvec_done' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_size' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_size' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_bvec_done' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_bvec_done' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_idx' in something not a structure or union
arch/xtensa/platforms/iss/simdisk.c:111:18: error: request for member 'bi_bvec_done' in something not a structure or union
make[2]: *** [arch/xtensa/platforms/iss/simdisk.o] Error 1

Fixup the usage of bio_for_each_segment(). Also fix wrong use
of __bio_kunmap_atomic() - it needs the mapped buffer passed in,
not the originally mapped page.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>