drm/mediatek: Fix using wrong drm private data to bind mediatek-drm

According to mtk_drm_kms_init(), the all_drm_private array in each
drm private data stores all drm private data in display path order.

In mtk_drm_get_all_drm_priv(), each element in all_drm_priv should have one
display path private data, such as:
all_drm_priv[CRTC_MAIN] should only have main_path data
all_drm_priv[CRTC_EXT] should only have ext_path data
all_drm_priv[CRTC_THIRD] should only have third_path data

So we need to add the length checking for each display path before
assigning their drm private data into all_drm_priv array.

Then the all_drm_private array in each drm private data needs to be
assigned in their display path order.

Fixes: 1ef7ed48 ("drm/mediatek: Modify mediatek-drm for mt8195 multi mmsys support")
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>
Tested-by: Fei Shao <fshao@chromium.org>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20231004024013.18956-4-jason-jh.lin@mediatek.com/


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