media: apple: isp: wmb() before GPIO write

Signed-off-by: Eileen Yoon <eyn@gmx.com>

Author: eiln

drivers/media/platform/apple/isp/isp-fw.c

@@ -278,6 +278,7 @@ static int isp_firmware_boot_stage2(struct apple_isp *isp)
 
 	isp_gpio_write32(isp, ISP_GPIO_0, args_iova);
 	isp_gpio_write32(isp, ISP_GPIO_1, 0x0);
+	wmb();
 
 	/* Wait for ISP_GPIO_7 to 0xf7fbdff9 -> 0x8042006 */
 	isp_gpio_write32(isp, ISP_GPIO_7, 0xf7fbdff9);