drm/amd/display: Set color_mgmt_changed to true on unsuspend

[ Upstream commit 2eb9dd497a698dc384c0dd3e0311d541eb2e13dd ]

Otherwise we can end up with a frame on unsuspend where color management
is not applied when userspace has not committed themselves.

Fixes re-applying color management on Steam Deck/Gamescope on S3 resume.

Signed-off-by: Joshua Ashton <joshua@froggi.es>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>