GPU-DRM-OMAP: Delete unnecessary checks before two function calls

The following functions test whether their argument is NULL and then
return immediately.
* backlight_device_unregister
* drm_gem_object_unreference_unlocked

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: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/72ff4670-4f3d-c7ed-4f37-e49f2bbc7aba@users.sourceforge.net
diff --git a/drivers/gpu/drm/omapdrm/omap_fb.c b/drivers/gpu/drm/omapdrm/omap_fb.c
index 983c8cf..31f5178 100644
--- a/drivers/gpu/drm/omapdrm/omap_fb.c
+++ b/drivers/gpu/drm/omapdrm/omap_fb.c
@@ -115,8 +115,8 @@
 
 	for (i = 0; i < n; i++) {
 		struct plane *plane = &omap_fb->planes[i];
-		if (plane->bo)
-			drm_gem_object_unreference_unlocked(plane->bo);
+
+		drm_gem_object_unreference_unlocked(plane->bo);
 	}
 
 	kfree(omap_fb);