stm32: adc-v2: extract common calibration code

Extract the calibration code from the f0, and share it with the other
adc-v2 peripheral users (f0,l0,f3,l4)

Uses the same naming set of is/async naming conventions requested by the
RTOS guys instead of having blocking only calls.

Old code:
	adc_calibrate_start(ADC);
	adc_calibrate_wait_finish(ADC);

New code (blocking):
	adc_calibrate(ADC);

New code (asynch):
	adc_calibrate_async(ADC);
	// do stuff
	adc_is_calibrating(ADC);  // will be false when it's finished.

Old code for f0 is still available, but marked deprecated.

lib/stm32/common/adc_common_v2.c

@@ -146,6 +146,37 @@ void adc_power_off(uint32_t adc)
 	while (!adc_is_power_off(adc));
 }
 
+/**
+ * Start the ADC calibration and immediately return.
+ * @sa adc_calibrate
+ * @sa adc_is_calibrate
+ * @param adc ADC Block register address base @ref adc_reg_base
+ */
+void adc_calibrate_async(uint32_t adc)
+{
+	ADC_CR(adc) = ADC_CR_ADCAL;
+}
+
+/**
+ * Is the ADC Calibrating?
+ * @param adc ADC Block register address base @ref adc_reg_base
+ * @return true if the adc is currently calibrating
+ */
+bool adc_is_calibrating(uint32_t adc)
+{
+	return (ADC_CR(adc) & ADC_CR_ADCAL);
+}
+
+/**
+ * Start ADC calibration and wait for it to finish
+ * @param adc ADC Block register address base @ref adc_reg_base
+ */
+void adc_calibrate(uint32_t adc)
+{
+	adc_calibrate_async(adc);
+	while (adc_is_calibrating(adc));
+}
+
 /**
  * Enable Continuous Conversion Mode
  * In this mode the ADC starts a new conversion of a single channel or a channel