drm/msm/mdp5: drop eDP support

Prepare for removing old eDP support present in 8x74/8x84 SoC families.
No devices present in mainline support eDP ports.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20211001165011.441945-2-dmitry.baryshkov@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>