emac_stm32: properly invalidate DCache before disabling it

Author: facchinm

connectivity/drivers/emac/TARGET_STM/TARGET_STM32H7/TARGET_OPTA/stm32h7_eth_init.c

@@ -66,7 +66,10 @@ void HAL_ETH_MspInit(ETH_HandleTypeDef *heth)
 
 #if !(defined(DUAL_CORE) && defined(CORE_CM4))
         /* Disable DCache for STM32H7 family */
+        core_util_critical_section_enter();
+        SCB_CleanInvalidateDCache();
         SCB_DisableDCache();
+        core_util_critical_section_exit();
 #endif
 
         /* GPIO Ports Clock Enable */

connectivity/drivers/emac/TARGET_STM/TARGET_STM32H7/TARGET_PORTENTA_H7/stm32h7_eth_init.c

@@ -68,6 +68,7 @@ void HAL_ETH_MspInit(ETH_HandleTypeDef *heth)
 #if !(defined(DUAL_CORE) && defined(CORE_CM4))
         /* Disable DCache for STM32H7 family */
         core_util_critical_section_enter();
+        SCB_CleanInvalidateDCache();
         SCB_DisableDCache();
         core_util_critical_section_exit();
 #endif