drm/amd/display: Load srm before enabling HDCP

[Why]
we need to load SRM before we start HDCP. Because for S3 case the sysfs call will be
after we have already enabled HDCP, so we might not be using the latest SRM

[How]
Set srm before starting HDCP.

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>