espressif:esp32s3: Add esp32s3 initial support

ESP32-S3 target and related files added to the Espressif port.

Signed-off-by: Almir Okato <almir.okato@espressif.com>
diff --git a/boot/espressif/CMakeLists.txt b/boot/espressif/CMakeLists.txt
index 1d8afb5..0aa9dc2 100644
--- a/boot/espressif/CMakeLists.txt
+++ b/boot/espressif/CMakeLists.txt
@@ -13,7 +13,8 @@
 add_definitions(-DMCUBOOT_TARGET=${MCUBOOT_TARGET})
 
 if ("${MCUBOOT_TARGET}" STREQUAL "esp32" OR
-    "${MCUBOOT_TARGET}" STREQUAL "esp32s2")
+    "${MCUBOOT_TARGET}" STREQUAL "esp32s2" OR
+    "${MCUBOOT_TARGET}" STREQUAL "esp32s3")
     set(MCUBOOT_ARCH "xtensa")
 elseif("${MCUBOOT_TARGET}" STREQUAL "esp32c3")
     set(MCUBOOT_ARCH "riscv")