esp_clk: Add migration guide for this breaking change

docs/en/migration-guides/system.rst

@@ -8,3 +8,14 @@ IPC (Inter-Processor Call) component has been moved to ``esp_system``.
 
 Thus, any project presenting a ``CMakeLists.txt`` file with the parameters ``PRIV_REQUIRES esp_ipc`` or ``REQUIRES esp_ipc``, should be modified to simply remove these options as ``esp_system`` component is included by default.
 
+ESP Clock
+---------
+
+The old headers ``target/clk.h``, ``esp_clk.h`` have been removed.
+
+Therefore, If you want to use the function with the prefix ``esp_clk`` please include ``esp_private/esp_clk.h`` instead.
+
+Cache Error Interrupt
+---------------------
+
+The old headers ``target/cache_err_int.h`` have been removed. Please include ``cache_err_int.h`` directly.