fip_create: Fix exit status for missing output filename

Change-Id: I0d298eea9eaf47121c87637c7395e5d9868aa272

tools/fip_create/fip_create.c

@@ -811,7 +811,7 @@ int main(int argc, char **argv)
 	if (fip_filename == NULL) {
 		printf("ERROR: Missing FIP filename\n");
 		print_usage();
-		return 0;
+		return EINVAL;
 	}
 
 	/* Unpack images from FIP always takes precedence over packaging. In