drm/msm: Delete unnecessary checks before drm_gem_object_unreference_unlocked()

The drm_gem_object_unreference_unlocked() function tests whether
its argument is NULL and then returns immediately.
Thus the test around the calls is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c

@@ -168,8 +168,7 @@ static void mdp4_destroy(struct msm_kms *kms)
 
 	if (mdp4_kms->blank_cursor_iova)
 		msm_gem_put_iova(mdp4_kms->blank_cursor_bo, mdp4_kms->id);
-	if (mdp4_kms->blank_cursor_bo)
-		drm_gem_object_unreference_unlocked(mdp4_kms->blank_cursor_bo);
+	drm_gem_object_unreference_unlocked(mdp4_kms->blank_cursor_bo);
 
 	if (mdp4_kms->rpm_enabled)
 		pm_runtime_disable(dev);

drivers/gpu/drm/msm/msm_fb.c

@@ -49,8 +49,8 @@ static void msm_framebuffer_destroy(struct drm_framebuffer *fb)
 
 	for (i = 0; i < n; i++) {
 		struct drm_gem_object *bo = msm_fb->planes[i];
-		if (bo)
-			drm_gem_object_unreference_unlocked(bo);
+
+		drm_gem_object_unreference_unlocked(bo);
 	}
 
 	kfree(msm_fb);

drivers/gpu/drm/msm/msm_gem.c

@@ -875,8 +875,6 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev,
 	return obj;
 
 fail:
-	if (obj)
-		drm_gem_object_unreference_unlocked(obj);
-
+	drm_gem_object_unreference_unlocked(obj);
 	return ERR_PTR(ret);
 }