esp_system: move brownout init due to dependency issue

components/esp_system/port/cpu_start.c

@@ -28,7 +28,6 @@
 
 #if CONFIG_IDF_TARGET_ESP32
 #include "esp32/cache_err_int.h"
-#include "esp32/brownout.h"
 #include "esp32/rom/cache.h"
 #include "esp32/rom/rtc.h"
 #include "esp32/rom/uart.h"

components/esp_system/startup.c

@@ -54,9 +54,11 @@
 #if CONFIG_IDF_TARGET_ESP32
 #include "esp32/rom/uart.h"
 #include "esp32/spiram.h"
+#include "esp32/brownout.h"
 #elif CONFIG_IDF_TARGET_ESP32S2
 #include "esp32s2/rom/uart.h"
 #include "esp32s2/spiram.h"
+#include "esp32s2/brownout.h"
 #endif
 /***********************************************/
 
@@ -181,6 +183,12 @@ static void IRAM_ATTR do_core_init(void)
 #endif
     }
 
+#if CONFIG_ESP32_BROWNOUT_DET || CONFIG_ESP32S2_BROWNOUT_DET
+    // [refactor-todo] leads to call chain rtc_is_register (driver) -> esp_intr_alloc (esp32/esp32s2) -> 
+    // malloc (newlib) -> heap_caps_malloc (heap), so heap must be at least initialized
+    esp_brownout_init();
+#endif
+
     // Now we have startup stack RAM available for heap, enable any DMA pool memory
 #if CONFIG_SPIRAM_MALLOC_RESERVE_INTERNAL
     if (g_spiram_ok) {