ns: drop assert

Otherwise we warn when e.g., no namespaces are configured but the
initial namespace for is still around.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

kernel/nscommon.c

@@ -46,8 +46,6 @@ static void ns_debug(struct ns_common *ns, const struct proc_ns_operations *ops)
 		VFS_WARN_ON_ONCE(ops != &utsns_operations);
 		break;
 #endif
-	default:
-		VFS_WARN_ON_ONCE(true);
 	}
 }
 #endif