Remove double error message for -device option parsing

qemu_opts_parse() gives a suitable error message in all failure cases
so we can remove the error message from the caller.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

vl.c

@@ -5359,9 +5359,7 @@ int main(int argc, char **argv, char **envp)
                 add_device_config(DEV_USB, optarg);
                 break;
             case QEMU_OPTION_device:
-                opts = qemu_opts_parse(&qemu_device_opts, optarg, "driver");
-                if (!opts) {
-                    fprintf(stderr, "parse error: %s\n", optarg);
+                if (!qemu_opts_parse(&qemu_device_opts, optarg, "driver")) {
                     exit(1);
                 }
                 break;