quota: Factor out setup of quota inode

Factor out setting up of quota inode and eventual error cleanup from
vfs_load_quota_inode(). This will simplify situation for filesystems
that don't have any quota inodes.

Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 185d948..2625766 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -89,6 +89,8 @@ int dquot_file_open(struct inode *inode, struct file *file);
 
 int dquot_enable(struct inode *inode, int type, int format_id,
 	unsigned int flags);
+int dquot_load_quota_sb(struct super_block *sb, int type, int format_id,
+	unsigned int flags);
 int dquot_quota_on(struct super_block *sb, int type, int format_id,
 	const struct path *path);
 int dquot_quota_on_mount(struct super_block *sb, char *qf_name,