[media] coda: fix build error by making reset control optional

make reset control optional for i.MX27

The patch "[media] coda: add reset control support" introduced a build failure
if CONFIG_RESET_CONTROLLER is disabled:

    drivers/media/platform/coda.c:3734:2: error: implicit declaration of
     function 'devm_reset_control_get'

Since not all SoCs containing CODA VPUs do have a system reset controller,
use devm_reset_control_get_optional to make it optional.

Reported-by: Shawn Guo <shawn.guo@linaro.org>
Reported-by: Olof's autobuilder <build@lixom.net>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/platform/coda.c

@@ -3780,10 +3780,10 @@ static int coda_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	dev->rstc = devm_reset_control_get(&pdev->dev, NULL);
+	dev->rstc = devm_reset_control_get_optional(&pdev->dev, NULL);
 	if (IS_ERR(dev->rstc)) {
 		ret = PTR_ERR(dev->rstc);
-		if (ret == -ENOENT) {
+		if (ret == -ENOENT || ret == -ENOSYS) {
 			dev->rstc = NULL;
 		} else {
 			dev_err(&pdev->dev, "failed get reset control: %d\n", ret);