drm/amd/display: Fix HDCP failing to enable after suspend

[Why]
On resume some displays are not ready for HDCP, so they will fail if we
start the hdcp authentintication too soon.

Add a delay so that the displays can be ready before we start.

NOTE: Previoulsy this delay was set to 3 seconds but it was causing
issues with compliance, 2 seconds should enough for compliance and the
s3 resume case.

[How]
Change the Delay to 2 seconds.

Reviewed-by: Aurabindo Pillai <Aurabindo.Pillai@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>