drm/msm: add HDMI support for DRM KMS driver

Add initial HDMI display driver support for SDE.
Support for configuring the HDMI TX controller
to specific resolutions. Add support for HDMI specific
ISR, uevent handling, basic debugfs support.
Add support for HDMI DRM specific calls for SDE driver.

Change-Id: I0cf7f4067e1a9b378632713b896798971971e5b9
Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>