drm/msm: Remove need for reiterating the compatibles

drm/msm: Remove need for reiterating the compatibles

After spending a non-negligible time trying to figure out why
dpu_kms_init() would dereference a NULL dpu_kms->pdev, it turns out that
in addition to adding the new compatible to the msm_drv of_match_table
one also need to teach add_display_components() to register the child
nodes - which includes the DPU platform_device.

Replace the open coded test for compatibles with a check against the
match data of the mdss device to save others this trouble in the future.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210317025634.3987908-1-bjorn.andersson@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>