disco_f769ni adding ethernet init

the IPV4 feature was already enabled in an earlier commit but the mbed 5 ethernet initialisation was missing

features/net/FEATURE_IPV4/lwip-interface/lwip-eth/arch/TARGET_STM/TARGET_STM32F7/TARGET_DISCO_F769NI/stm32f7_eth_init.c

@@ -0,0 +1,87 @@
+#include "stm32f7xx_hal.h"
+
+/**
+ * Override HAL Eth Init function
+ */
+void HAL_ETH_MspInit(ETH_HandleTypeDef* heth)
+{
+    GPIO_InitTypeDef GPIO_InitStructure;
+    if (heth->Instance == ETH) {
+
+        /* Enable GPIOs clocks */
+        __HAL_RCC_GPIOA_CLK_ENABLE();
+        __HAL_RCC_GPIOC_CLK_ENABLE();
+        __HAL_RCC_GPIOD_CLK_ENABLE();
+        __HAL_RCC_GPIOG_CLK_ENABLE();
+
+        /** ETH GPIO Configuration
+          RMII_REF_CLK ----------------------> PA1
+          RMII_MDIO -------------------------> PA2
+          RMII_MDC --------------------------> PC1
+          RMII_MII_CRS_DV -------------------> PA7
+          RMII_MII_RXD0 ---------------------> PC4
+          RMII_MII_RXD1 ---------------------> PC5
+          RMII_MII_RXER ---------------------> PD5
+          RMII_MII_TX_EN --------------------> PG11
+          RMII_MII_TXD0 ---------------------> PG13
+          RMII_MII_TXD1 ---------------------> PG14
+         */
+        /* Configure PA1, PA2 and PA7 */
+        GPIO_InitStructure.Speed = GPIO_SPEED_HIGH;
+        GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
+        GPIO_InitStructure.Pull = GPIO_NOPULL; 
+        GPIO_InitStructure.Alternate = GPIO_AF11_ETH;
+        GPIO_InitStructure.Pin = GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_7;
+        HAL_GPIO_Init(GPIOA, &GPIO_InitStructure);
+
+        /* Configure PC1, PC4 and PC5 */
+        GPIO_InitStructure.Pin = GPIO_PIN_1 | GPIO_PIN_4 | GPIO_PIN_5;
+        HAL_GPIO_Init(GPIOC, &GPIO_InitStructure);
+
+        /* Configure PD5 */
+        GPIO_InitStructure.Pin =  GPIO_PIN_5;
+        HAL_GPIO_Init(GPIOD, &GPIO_InitStructure);
+
+        /* Configure PG11, PG13 and PG14 */
+        GPIO_InitStructure.Pin =  GPIO_PIN_11 | GPIO_PIN_13 | GPIO_PIN_14;
+        HAL_GPIO_Init(GPIOG, &GPIO_InitStructure);
+
+        /* Enable the Ethernet global Interrupt */
+        HAL_NVIC_SetPriority(ETH_IRQn, 0x7, 0);
+        HAL_NVIC_EnableIRQ(ETH_IRQn);
+
+        /* Enable ETHERNET clock  */
+        __HAL_RCC_ETH_CLK_ENABLE();
+    }
+}
+
+/**
+ * Override HAL Eth DeInit function
+ */
+void HAL_ETH_MspDeInit(ETH_HandleTypeDef* heth)
+{
+    if (heth->Instance == ETH) {
+        /* Peripheral clock disable */
+        __HAL_RCC_ETH_CLK_DISABLE();
+
+        /** ETH GPIO Configuration
+          RMII_REF_CLK ----------------------> PA1
+          RMII_MDIO -------------------------> PA2
+          RMII_MDC --------------------------> PC1
+          RMII_MII_CRS_DV -------------------> PA7
+          RMII_MII_RXD0 ---------------------> PC4
+          RMII_MII_RXD1 ---------------------> PC5
+          RMII_MII_RXER ---------------------> PD5
+          RMII_MII_TX_EN --------------------> PG11
+          RMII_MII_TXD0 ---------------------> PG13
+          RMII_MII_TXD1 ---------------------> PG14
+         */
+        HAL_GPIO_DeInit(GPIOA, GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_7);
+        HAL_GPIO_DeInit(GPIOC, GPIO_PIN_1 | GPIO_PIN_4 | GPIO_PIN_5);
+        HAL_GPIO_DeInit(GPIOD, GPIO_PIN_5);
+        HAL_GPIO_DeInit(GPIOG, GPIO_PIN_11 | GPIO_PIN_13 | GPIO_PIN_14);
+
+        /* Disable the Ethernet global Interrupt */
+        NVIC_DisableIRQ(ETH_IRQn);
+    }
+}