[PATCH] FAT: DIO-write fallback to normal buffered

If the DIO write on FAT is expanding the size, it will be fail by -EINVAL,
because FAT can't handle it now.

This patch fallback it to the normal buffered-write and would return
success.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>