drm/amd/display: Check HDCP returned status

[ Upstream commit 5d93060d ]

[WHAT & HOW]
Check mod_hdcp_execute_and_set() return values in authenticated_dp.

This fixes 3 CHECKED_RETURN issues reported by Coverity.

Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>