xtensa: remove the second argument of __bio_kmap_atomic()

kmap_atomic allows only one argument now, just remove the unused 'kmtype'.

Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Chris Zankel <chris@zankel.net>