esp_system: remove duplicated esp_digital_reset function

esp_digital_reset was defined both in system_api.c and panic_handler.c

components/esp_common/include/esp_private/system_internal.h

@@ -36,6 +36,11 @@ extern "C" {
  */
 void esp_restart_noos(void) __attribute__ ((noreturn));
 
+/**
+ * @brief Similar to esp_restart_noos, but resets all the digital peripherals.
+ */
+void esp_restart_noos_dig(void) __attribute__ ((noreturn));
+
 /**
  * @brief  Internal function to set reset reason hint
  *