[why]
Most DP/HDMI monitors need more time to response rx_validation
request.

[how]
Add generic 1000ms delay.
Signed-off-by: Jing Zhou <Jing.Zhou@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>