Merge branch 'bugfix/reset_some_peripherals_when_cpu_start' into 'master'

driver:   Reset  communication peripherals when cpu start up.

See merge request idf/esp-idf!2296

components/driver/uart.c

@@ -651,6 +651,9 @@ esp_err_t uart_param_config(uart_port_t uart_num, const uart_config_t *uart_conf
     r = uart_set_tx_idle_num(uart_num, UART_TX_IDLE_NUM_DEFAULT);
     if (r != ESP_OK) return r;
     r = uart_set_stop_bits(uart_num, uart_config->stop_bits);
+    //A hardware reset does not reset the fifo,
+    //so we need to reset the fifo manually.
+    uart_reset_rx_fifo(uart_num);
     return r;
 }