drm/msm/dpu: remove phys_vid subclass

Not holding any video encoder specific data. Get rid of it.

Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1550107156-17625-3-git-send-email-jsanka@codeaurora.org


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