add flash and PSRAM CS IO acquire function

components/esp_hw_support/include/soc/esp32s3/spiram.h

@@ -79,6 +79,16 @@ void esp_spiram_writeback_cache(void);
  */
 bool esp_spiram_is_initialized(void);
 
+/**
+ * @brief get psram CS IO
+ *
+ * This interface should be called after PSRAM is enabled, otherwise it will
+ * return an invalid value -1/0xff.
+ *
+ * @return psram CS IO or -1/0xff if psram not enabled
+ */
+uint8_t esp_spiram_get_cs_io(void);
+
 /**
  * @brief Reserve a pool of internal memory for specific DMA/internal allocations
  *