Since some SoCs support premultiplied pixel formats but some do not,
the blend_modes parameter is added to mtk_plane_init(), which is
obtained from the mtk_ddp_comp_get_blend_modes function implemented
in different OVL components.
The OVL component can use driver data to set the blend mode
capabilities for different SoCs.
Fixes: 4225d5d5e779 ("drm/mediatek: Support alpha blending in display driver")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>