drm/msi/mdp4: populate priv->kms in mdp4_kms_init

Without this fix boot throws NULL ptr exception at msm_dsi_manager_setup_encoder
on devices like Nexus 7 2013 (MDP4 v4.4).

Fixes: 03436e3e ("drm/msm/dsi: Move setup_encoder to modeset_init")

Cc: <stable@vger.kernel.org>
Signed-off-by: David Heidelberg <david@ixit.cz>
Link: https://lore.kernel.org/r/20210811170631.39296-1-david@ixit.cz


Signed-off-by: Rob Clark <robdclark@chromium.org>