drm/amdgpu: Switch user queues to use preempt/restore for eviction

drm/amdgpu: Switch user queues to use preempt/restore for eviction

This patch modifies the user queue management to use preempt/restore
operations instead of full map/unmap for queue eviction scenarios where
applicable. The changes include:

1. Introduces new helper functions:
   - amdgpu_userqueue_preempt_helper()
   - amdgpu_userqueue_restore_helper()

2. Updates queue state management to track PREEMPTED state

3. Modifies eviction handling to use preempt instead of unmap:
   - amdgpu_userq_evict_all() now uses preempt_helper
   - amdgpu_userq_restore_all() now uses restore_helper

The preempt/restore approach provides better performance during queue
eviction by avoiding the overhead of full queue teardown and setup.
Full map/unmap operations are still used for initial setup/teardown
and system suspend scenarios.

v2: rename amdgpu_userqueue_restore_helper/amdgpu_userqueue_preempt_helper to
amdgpu_userq_restore_helper/amdgpu_userq_preempt_helper for consistency. (Alex)

v3: amdgpu_userq_stop_sched_for_enforce_isolation() and
amdgpu_userq_start_sched_for_enforce_isolation() should use preempt and restore (Alex)

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>