fix(ram_app): Fixed issue ram_app can't use the SPI Flash

1st bootloader won't help to initialize the MSPI & cache properly as it
usually do when loading from flash. And the ram app doesn't have valid
headers.

Since there is no enough space in 2nd bootloader, we replace the
`bootloader_init_spi_flash` in the ram_app (!pure_ram_app), with an
customized alternative of it for the ram_app.

This alternative helps to initialize the MSPI & cache properly, without
the help of 1st bootloader or image headers.

components/bootloader_support/bootloader_flash/include/esp_private/bootloader_flash_internal.h

@@ -18,6 +18,15 @@ extern "C" {
  */
 esp_err_t bootloader_init_spi_flash(void);
 
+#if CONFIG_APP_BUILD_TYPE_RAM && !CONFIG_APP_BUILD_TYPE_PURE_RAM_APP
+/**
+ * @brief Config all flash related stuff according to the header. The consistency of all flash configs is ensured.
+ *
+ * @return None
+ */
+void bootloader_flash_hardware_init(void);
+#endif
+
 #ifdef __cplusplus
 }
 #endif