drm/panfrost: Fix missing clk_disable_unprepare() on error in panfrost_clk_init()

Fix the missing clk_disable_unprepare() before return
from panfrost_clk_init() in the error handling case.

Fixes: b681af0b ("drm: panfrost: add optional bus_clock")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210608143856.4154766-1-weiyongjun1@huawei.com

drivers/gpu/drm/panfrost/panfrost_device.c

@@ -54,7 +54,8 @@ static int panfrost_clk_init(struct panfrost_device *pfdev)
 	if (IS_ERR(pfdev->bus_clock)) {
 		dev_err(pfdev->dev, "get bus_clock failed %ld\n",
 			PTR_ERR(pfdev->bus_clock));
-		return PTR_ERR(pfdev->bus_clock);
+		err = PTR_ERR(pfdev->bus_clock);
+		goto disable_clock;
 	}
 
 	if (pfdev->bus_clock) {