Add missing ADC clock config for Generic F103xE

Signed-off-by: Frederic Pillon <[email protected]>

Author: fpistm

Diff for: variants/Generic_F103Rx/variant.cpp

@@ -120,7 +120,8 @@ WEAK void SystemClock_Config(void)
   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) {
     Error_Handler();
   }
-  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB;
+  PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_ADC | RCC_PERIPHCLK_USB;
+  PeriphClkInit.AdcClockSelection = RCC_ADCPCLK2_DIV6;
   PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLL_DIV1_5;
   if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) {
     Error_Handler();