add esp32s2 saola bsp

update cdc_msc_freertos main.c to work with esp32s2
add CMake file

hw/bsp/esp32s2_saola/esp32s2_saola.c

@@ -0,0 +1,77 @@
+/* 
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020, Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * This file is part of the TinyUSB stack.
+ */
+
+#include "bsp/board.h"
+#include "driver/gpio.h"
+#include "hal/usb_hal.h"
+
+//--------------------------------------------------------------------+
+// MACRO TYPEDEF CONSTANT ENUM DECLARATION
+//--------------------------------------------------------------------+
+
+#define LED_PIN   21
+
+// Initialize on-board peripherals : led, button, uart and USB
+void board_init(void)
+{
+  // LED
+  gpio_pad_select_gpio(LED_PIN);
+  gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT);
+
+  // USB Controller Hal init
+  usb_hal_context_t hal = {
+    .use_external_phy = false // use built-in PHY
+  };
+  usb_hal_init(&hal);
+}
+
+// Turn LED on or off
+void board_led_write(bool state)
+{
+  gpio_set_level(LED_PIN, state);
+}
+
+// Get the current state of button
+// a '1' means active (pressed), a '0' means inactive.
+uint32_t board_button_read(void)
+{
+  return 0;
+}
+
+// Get characters from UART
+int board_uart_read(uint8_t* buf, int len)
+{
+  (void) buf; (void) len;
+  return 0;
+}
+
+// Send characters to UART
+int board_uart_write(void const * buf, int len)
+{
+  (void) buf; (void) len;
+  return 0;
+}
+