adl: unambiguosly check if FanSpeedInfo specifies support for either mechanism to set FanSpeed.

Reported by olejr: https://github.com/veox/sgminer/issues/15#issuecomment-32715082

Related issue: https://github.com/veox/sgminer/issues/15

adl.c

@@ -538,6 +538,9 @@ void init_adl(int nDevs)
 
 		if (ADL_Overdrive5_FanSpeedInfo_Get(iAdapterIndex, 0, &ga->lpFanSpeedInfo) != ADL_OK)
 			applog(LOG_INFO, "Failed to ADL_Overdrive5_FanSpeedInfo_Get");
+
+		if(!(ga->lpFanSpeedInfo.iFlags & (ADL_DL_FANCTRL_SUPPORTS_RPM_WRITE | ADL_DL_FANCTRL_SUPPORTS_PERCENT_WRITE)))
+			ga->has_fanspeed = false;
 		else
 			ga->has_fanspeed = true;