drm/msm: add support for parsing hdmi/hdcp capabilities

Add support to parse the HDMI TX version and
HDCP support from the HDMI and QFPROM registers.

This information is used to decide which HDCP driver
module is to be initialized at boot time.

Change-Id: Ib598f3867f1cd2ef9adb7503c5907cbb1e4ba758
Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>