drm/amd/display: Add stub to get DPIA tunneling device data

[why & how]
1. Add stub for getting tunneling device data
2. Add check for phy_repeater_cnt < 0xff to LTTPR check
3. Add two more bits of information to DPIA links

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Acked-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Jimmy Kizito <Jimmy.Kizito@amd.com>