drm/amd/display: enable hostvm based on roimmu active for dcn2.1

drm/amd/display: enable hostvm based on roimmu active for dcn2.1

[ Upstream commit 48d92e8eda3d9b61978377e7539bfc5958e850cf ]

Enabling hostvm when ROIMMU is not active seems to break GPUVM.
This fixes the issue by not enabling hostvm if ROIMMU is not
activated.

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Roman Li <Roman.Li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>