change(xtensa): Deprecate ".../xtensa_context.h" include path

This commit deprecates the "freertos/xtensa_context.h" and "xtensa/xtensa_context.h"
include paths. Users should use "xtensa_context.h" instead.

- Replace legacy include paths
- Removed some unnecessary includes of "xtensa_api.h"
- Add warning to compatibility header

components/esp_gdbstub/src/port/xtensa/include/esp_gdbstub_arch.h

@@ -6,7 +6,7 @@
 
 #pragma once
 #include <stdint.h>
-#include "freertos/xtensa_context.h"
+#include "xtensa_context.h"
 #include "sdkconfig.h"
 
 #if CONFIG_IDF_TARGET_ESP32

components/esp_gdbstub/src/port/xtensa/xt_debugexception.S

@@ -7,7 +7,7 @@
 #include <xtensa/coreasm.h>
 #include <xtensa/corebits.h>
 #include <xtensa/config/system.h>
-#include "freertos/xtensa_context.h"
+#include "xtensa_context.h"
 
     .section    .iram1,"ax"
     .global     _xt_panic_gdbstub