fs/9p: Fix the return error on default acl removal

If we don't have default ACL, then trying to remove
default acl on a file should return 0.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

fs/9p/acl.c

@@ -365,7 +365,7 @@ static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
 	case ACL_TYPE_DEFAULT:
 		name = POSIX_ACL_XATTR_DEFAULT;
 		if (!S_ISDIR(inode->i_mode)) {
-			retval = -EINVAL;
+			retval = acl ? -EINVAL : 0;
 			goto err_out;
 		}
 		break;