ndevs: get vendor names on windows too

ccminer -n 2>NUL

GPU #0: SM 5.2 GeForce GTX 970
GPU #1: SM 5.0 Gigabyte GTX 750 Ti
GPU #2: SM 5.2 ASUS GTX 970

note: nvml destroy is made in proper_exit function

ccminer.cpp

@@ -2463,6 +2463,13 @@ void parse_arg(int key, char *arg)
 		opt_statsavg = v;
 		break;
 	case 'n': /* --ndevs */
+		// to get gpu vendors...
+		#ifdef USE_WRAPNVML
+		hnvml = nvml_create();
+		#ifdef WIN32
+		if (!hnvml) nvapi_init();
+		#endif
+		#endif
 		cuda_print_devices();
 		proper_exit(EXIT_CODE_OK);
 		break;