drm/msm/dp: remove most of usbpd-related remains

Remove most of remains of downstream usbpd code. Mainline kernel uses
different approach for managing Type-C / USB-PD, so this remains unused.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Patchwork: https://patchwork.freedesktop.org/patch/538270/
Link: https://lore.kernel.org/r/20230520182050.4014143-1-dmitry.baryshkov@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>