BACKPORT: f2fs: clean up f2fs_abort_atomic_write()

f2fs_abort_atomic_write() has checked whether current inode is
atomic_write one or not, it's redundant to check in its caller,
remove it for cleanup.

Bug: 298879042
Change-Id: Id8853bfa89eb2224d9c36efc0febf208b454e7c7
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
(cherry picked from commit 24e91204)
Signed-off-by: zhoudan8 <zhoudan8@xiaomi.com>