drm/amd/display: Enable idle workqueue for more IPS modes

[Why]

There are more IPS modes other than DMUB_IPS_ENABLE that enables IPS. We
need to enable the hotplug detect idle workqueue for those modes as
well.

[How]

Modify the if condition to initialize the workqueue in all IPS modes
except for DMUB_IPS_DISABLE_ALL.

Fixes: 65444581 ("drm/amd/display: Determine IPS mode by ASIC and PMFW versions")
Signed-off-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>