drm/msm: dpu: Remove checks from dpu_plane_destroy_state()

They're not needed.

Reviewed-by: Jeykumar Sankaran <[e-mail]>
Signed-off-by: Sean Paul <[e-mail]>
Signed-off-by: Rob Clark <[e-mail]>

drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c

···
 static void dpu_plane_destroy_state(struct drm_plane *plane,
 		struct drm_plane_state *state)
 {
-	struct dpu_plane_state *pstate;
-
-	if (!plane || !state) {
-		DPU_ERROR("invalid arg(s), plane %d state %d\n",
-				plane != 0, state != 0);
-		return;
-	}
-
-	pstate = to_dpu_plane_state(state);
-
 	__drm_atomic_helper_plane_destroy_state(state);
-
-	kfree(pstate);
+	kfree(to_dpu_plane_state(state));
 }
 
 static struct drm_plane_state *