ethernet: enlarge ethernet task stack size

1. In original driver, the stack size for emac driver task "emacT" is only 2048 Bytes, which also can not be changed by user.
2. Each time when invoking "emac_start" function, it will reset emac registers, the driver should reconfig some important registers again.

components/ethernet/Kconfig

@@ -50,4 +50,11 @@ config EMAC_TASK_PRIORITY
     help
         Ethernet MAC task priority.
 
+config EMAC_TASK_STACK_SIZE
+    int "Stack Size of EMAC Task"
+    default 3072
+    range 2000 8000
+    help
+        Stack Size of Ethernet MAC task.
+
 endmenu

components/ethernet/emac_common.h

@@ -106,6 +106,7 @@ struct emac_close_cmd {
 #define DMA_RX_BUF_NUM CONFIG_DMA_RX_BUF_NUM
 #define DMA_TX_BUF_NUM CONFIG_DMA_TX_BUF_NUM
 #define EMAC_TASK_PRIORITY CONFIG_EMAC_TASK_PRIORITY
+#define EMAC_TASK_STACK_SIZE  CONFIG_EMAC_TASK_STACK_SIZE
 
 #define DMA_RX_BUF_SIZE 1600
 #define DMA_TX_BUF_SIZE 1600

components/ethernet/emac_main.c

@@ -816,6 +816,7 @@ static void emac_start(void *param)
     emac_enable_clk(true);
 
     emac_reset();
+    emac_dma_init();
 
     emac_set_macaddr_reg();
 
@@ -1155,8 +1156,8 @@ esp_err_t esp_eth_init_internal(eth_config_t *config)
     emac_rx_xMutex = xSemaphoreCreateRecursiveMutex();
     emac_tx_xMutex = xSemaphoreCreateRecursiveMutex();
     emac_xqueue = xQueueCreate(EMAC_EVT_QNUM, sizeof(emac_event_t));
-    xTaskCreate(emac_task, "emacT", 2048, NULL, EMAC_TASK_PRIORITY,
-                &emac_task_hdl);
+    xTaskCreate(emac_task, "emacT", EMAC_TASK_STACK_SIZE, NULL,
+                EMAC_TASK_PRIORITY, &emac_task_hdl);
 
     emac_enable_clk(false);
     esp_intr_alloc(ETS_ETH_MAC_INTR_SOURCE, 0, emac_process_intr, NULL, NULL);