drm/msm: Fix missing unlock on error in msm_fbdev_create()

Add the missing unlock before return from function msm_fbdev_create()
in the error handling case.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_fbdev.c

@@ -143,7 +143,7 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
 	ret = msm_gem_get_iova_locked(fbdev->bo, 0, &paddr);
 	if (ret) {
 		dev_err(dev->dev, "failed to get buffer obj iova: %d\n", ret);
-		goto fail;
+		goto fail_unlock;
 	}
 
 	fbi = framebuffer_alloc(0, dev->dev);