xsk: Fix umem fill/completion queue mmap on 32-bit

With gcc-4.1.2 on 32-bit:

    net/xdp/xsk.c:663: warning: integer constant is too large for ‘long’ type
    net/xdp/xsk.c:665: warning: integer constant is too large for ‘long’ type

Add the missing "ULL" suffixes to the large XDP_UMEM_PGOFF_*_RING values
to fix this.

    net/xdp/xsk.c:663: warning: comparison is always false due to limited range of data type
    net/xdp/xsk.c:665: warning: comparison is always false due to limited range of data type

"unsigned long" is 32-bit on 32-bit systems, hence the offset is
truncated, and can never be equal to any of the XDP_UMEM_PGOFF_*_RING
values.  Use loff_t (and the required cast) to fix this.

Fixes: 423f3832 ("xsk: add umem fill queue support and mmap")
Fixes: fe230832

 ("xsk: add umem completion queue support and mmap")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>