BACKPORT: f2fs: avoid unneeded error handling for revoke_entry_slab allocation

In __f2fs_commit_atomic_write(), we will guarantee success of
revoke_entry_slab allocation, so let's avoid unneeded error handling.

Bug: 298879042
Bug: 308706939
Change-Id: I77a725f86034a4ab28eb1d8ecd56c3eb88660129
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
(cherry picked from commit f9a80689)
Signed-off-by: zhoudan8 <zhoudan8@xiaomi.com>