drm/msm/dp: add displayPort driver support

Add the needed displayPort files to enable DP driver
on msm target.

"dp_display" module is the main module that calls into
other sub-modules. "dp_drm" file represents the interface
between DRM framework and DP driver.

Changes in v12:

-- Add support of pm ops in display port driver
-- Clear bpp depth bits before writing to MISC register
-- Fix edid read

Previous Change log:
https://lkml.kernel.org/lkml/20200818051137.21478-3-tanmay@codeaurora.org/

Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>
Signed-off-by: Vara Reddy <varar@codeaurora.org>
Signed-off-by: Tanmay Shah <tanmay@codeaurora.org>
Co-developed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>
Co-developed-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Co-developed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Guenter Roeck <groeck@chromium.org>
Co-developed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>