Btrfs: fix fspath error deallocation

Make sure to deallocate fspath with vfree() in case of error in
init_ipath().

fspath is allocated with vmalloc() in init_data_container() since
commit 425d17a2 ("Btrfs: use larger limit for translation of logical to
inode").
Signed-off-by: Vincent Stehlé <vincent.stehle@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/backref.c

@@ -1991,7 +1991,7 @@ struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
 
 	ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
 	if (!ifp) {
-		kfree(fspath);
+		vfree(fspath);
 		return ERR_PTR(-ENOMEM);
 	}