espressif: Add ESP32-S2 initial basic support

ESP32S2 target added to the Espressif port, modified CMakeLists,
and added the bootloader related files to esp32s2 target directory.

Signed-off-by: Almir Okato <almir.okato@espressif.com>
diff --git a/boot/espressif/port/esp_mcuboot.c b/boot/espressif/port/esp_mcuboot.c
index ae40779..a80a859 100644
--- a/boot/espressif/port/esp_mcuboot.c
+++ b/boot/espressif/port/esp_mcuboot.c
@@ -231,12 +231,12 @@
 
 int flash_area_id_from_image_slot(int slot)
 {
-  return flash_area_id_from_multi_image_slot(0, slot);
+    return flash_area_id_from_multi_image_slot(0, slot);
 }
 
 int flash_area_to_sectors(int idx, int *cnt, struct flash_area *fa)
 {
-	return -1;
+    return -1;
 }
 
 void mcuboot_assert_handler(const char *file, int line, const char *func)