drivers/ADC: STM32: This solves coverity reported in ADC driver.

This commit it to resolve following bugs:
* Operands don't affect result.
* Logical dead code in stm32_adc driver.
Above mentioned bugs were solved by adding parenthesis and
changed the method of comparing. Since comparison of ADC
channel_id with the channel may cause loss of value.
So instead of direct comparison, introduced a mechanism to
convert channel constant to a decimal using
__LL_ADC_CHANNEL_TO_DECIMAL_NB() and strips away
the INTERNAL_CH bit and then compare with channel_id.

fix:
* #35130
* #35136

Signed-off-by: Affrin Pinhero <[email protected]>

Author: affrinpinhero-2356

drivers/adc/adc_stm32.c

@@ -567,8 +567,8 @@ static int adc_stm32_channel_setup(const struct device *dev,
 		return -EINVAL;
 	}
 
-	if (channel_cfg->channel_id == ADC_CHANNEL_TEMPSENSOR ||
-		channel_cfg->channel_id == ADC_CHANNEL_VREFINT) {
+	if ((__LL_ADC_CHANNEL_TO_DECIMAL_NB(ADC_CHANNEL_TEMPSENSOR) == channel_cfg->channel_id) ||
+		(__LL_ADC_CHANNEL_TO_DECIMAL_NB(ADC_CHANNEL_VREFINT) == channel_cfg->channel_id)) {
 		adc_stm32_set_common_path(dev);
 	}