drm/mediatek: Remove freeing not dynamic allocated memory

Fixing the coverity issue of:
mtk_drm_cmdq_pkt_destroy frees address of mtk_crtc->cmdq_handle

So remove the free function.

Fixes: 7627122f ("drm/mediatek: Add cmdq_handle in mtk_crtc")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20230714094908.13087-2-jason-jh.lin@mediatek.com/


Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>