drm/mediatek: mtk_drm_plane: Use kmalloc in mtk_plane_duplicate_state

There is no need to zero out the newly allocated memory because we are
duplicating all members of struct mtk_plane_state: switch to kmalloc
to save some overhead.

Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220118133759.112458-1-angelogioacchino.delregno@collabora.com/Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

drivers/gpu/drm/mediatek/mtk_drm_plane.c

@@ -57,7 +57,7 @@ static struct drm_plane_state *mtk_plane_duplicate_state(struct drm_plane *plane
 	struct mtk_plane_state *old_state = to_mtk_plane_state(plane->state);
 	struct mtk_plane_state *state;
 
-	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	state = kmalloc(sizeof(*state), GFP_KERNEL);
 	if (!state)
 		return NULL;