f2fs: use inner macro GFP_F2FS_ZERO for simplification

Use inner macro GFP_F2FS_ZERO to instead of GFP_NOFS | __GFP_ZERO for
simplification of code.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index dd55074..22b07c3 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -332,7 +332,7 @@
 {
 	struct f2fs_inode_info *fi;
 
-	fi = kmem_cache_alloc(f2fs_inode_cachep, GFP_NOFS | __GFP_ZERO);
+	fi = kmem_cache_alloc(f2fs_inode_cachep, GFP_F2FS_ZERO);
 	if (!fi)
 		return NULL;