nvml: fully disable it on windows

The DLL exists for x64 targets but seems not loadable

The nvml.cpp code was wrote to support both NVAPI and NVML on windows
because both apis have unique "features". like Fan RPM vs Fan Percent

ccminer.cpp

@@ -2207,12 +2207,13 @@ int main(int argc, char *argv[])
 	}
 
 #ifdef USE_WRAPNVML
-	// todo: link threads info gpu
+#ifndef WIN32
+	/* nvml is currently not usable on Windows (even for x64) */
 	hnvml = wrap_nvml_create();
 	if (hnvml)
 		applog(LOG_INFO, "NVML GPU monitoring enabled.");
-#ifdef WIN32 /* _WIN32 = x86 only, WIN32 for both _WIN32 & _WIN64 */
-	else if (wrap_nvapi_init() == 0)
+#else
+	if (wrap_nvapi_init() == 0)
 		applog(LOG_INFO, "NVAPI GPU monitoring enabled.");
 #endif
 	else