x86/mid/thermal: Turn off thermistor

Instead of complaining that the voltage is on, we can just ask
the MSIC to turn the voltage off. This should save some power.

Voltage for thermistors is turned on when ADC conversion is
initiated.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Acked-by: Durgadoss R <durgadoss.r@intel.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-85zdo06yve1o27jpwc74gzng@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/platform/x86/intel_mid_thermal.c

@@ -360,8 +360,10 @@ static int mid_initialize_adc(struct device *dev)
 	if (ret)
 		return ret;
 
-	if (data & MSIC_ADCTHERM_MASK)
-		dev_warn(dev, "ADCTHERM already set");
+	data &= ~MSIC_ADCTHERM_MASK;
+	ret = intel_msic_reg_write(INTEL_MSIC_ADC1CNTL3, data);
+	if (ret)
+		return ret;
 
 	/* Index of the first channel in which the stop bit is set */
 	channel_index = find_free_channel();