change(example): sleep iram optimization support for esp_timer demo

examples/system/esp_timer/main/esp_timer_example_main.c

@@ -71,7 +71,6 @@ void app_main(void)
     int64_t t2 = esp_timer_get_time();
     ESP_LOGI(TAG, "Woke up from light sleep, time since boot: %lld us", t2);
 
-    // TODO: PM-232
     assert(((t2 - t1 - 500000) < 1000) && ((t2 - t1 - 500000) > -2000));
 #endif
 

examples/system/esp_timer/sdkconfig.defaults

@@ -4,3 +4,6 @@ CONFIG_ESP_TIMER_PROFILING=y
 # LIBC_NEWLIB_NANO_FORMAT is enabled by default on ESP32-C2
 # This example needs 64-bit integer formatting, this is why this option is disabled
 CONFIG_LIBC_NEWLIB_NANO_FORMAT=n
+
+# Put sleep related source code in IRAM
+CONFIG_PM_SLP_IRAM_OPT=y