misc: fs_loader: Use buffer pointer in request_firmware_into_buf_via_script()

Use plain buffer pointer in request_firmware_into_buf_via_script()
instead of a pointer to pointer. The later is not necessary as the
request_firmware_into_buf_via_script() does not modify the buffer
pointer. Update the mediatek driver to match.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Weijie Gao <weijie.gao@mediatek.com>

include/fs_loader.h

@@ -87,7 +87,7 @@ int get_fs_loader(struct udevice **dev);
  *   env set fw_addr ${loadaddr} && env set fw_size ${filesize}
  * Return: 0 on success, negative value on error.
  */
-int request_firmware_into_buf_via_script(void **buf, size_t max_size,
+int request_firmware_into_buf_via_script(void *buf, size_t max_size,
 					 const char *script_name,
 					 size_t *retsize);
 #endif