f2fs: initialize page_array_entry slab only if compression feature is on

Otherwise, in image which doesn't support compression feature,
page_array_entry will be initialized w/o use.
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/compress.c

@@ -1908,6 +1908,9 @@ int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi)
 	dev_t dev = sbi->sb->s_bdev->bd_dev;
 	char slab_name[32];
 
+	if (!f2fs_sb_has_compression(sbi))
+		return 0;
+
 	sprintf(slab_name, "f2fs_page_array_entry-%u:%u", MAJOR(dev), MINOR(dev));
 
 	sbi->page_array_slab_size = sizeof(struct page *) <<