ANDROID: include: drm: add the definitions for DP Link Compliance tests

Add the definitions for various DPCD register offsets and
corresponding parameter values for DP Link compliance tests
for PHY audio/link training/link status tests.

Signed-off-by: Shashank Babu Chinta Venkata <sbchin@codeaurora.org>
Bug: 139653858
Change-Id: If6aa7d9b77e6234780086f27515c346b6495a46f
Signed-off-by: Matthias Maennich <maennich@google.com>