f2fs: use unlikely for release case

Since the variable release is only nonzero when another unlikely
case occurs, use unlikely() on it seems logical.
Signed-off-by: Fan li <fanofcode.li@samsung.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/f2fs.h

@@ -1594,7 +1594,7 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
 	}
 	spin_unlock(&sbi->stat_lock);
 
-	if (release)
+	if (unlikely(release))
 		dquot_release_reservation_block(inode, release);
 	f2fs_i_blocks_write(inode, *count, true, true);
 	return 0;