[HAL][ADC] Add UNUSED() macro to avoid the generation of a warning related to the unused argument 'hadc'

Src/stm32f3xx_hal_adc_ex.c

diff --git a/Src/stm32f3xx_hal_adc_ex.c b/Src/stm32f3xx_hal_adc_ex.c
index ff1f54e..6df572f 100644
--- a/Src/stm32f3xx_hal_adc_ex.c
+++ b/Src/stm32f3xx_hal_adc_ex.c
@@ -4853,7 +4853,10 @@
   
   /* Check the parameters */
   assert_param(IS_ADC_MULTIMODE_MASTER_INSTANCE(hadc->Instance));
-  
+
+  /* Prevent unused argument(s) compilation warning */
+  UNUSED(hadc);
+
   /* Pointer to the common control register to which is belonging hadc        */
   /* (Depending on STM32F3 product, there may be up to 4 ADC and 2 common     */
   /* control registers)                                                       */