drm/amdgpu: prevent immediate PASID reuse case

drm/amdgpu: prevent immediate PASID reuse case

PASID resue could cause interrupt issue when process
immediately runs into hw state left by previous
process exited with the same PASID, it's possible that
page faults are still pending in the IH ring buffer when
the process exits and frees up its PASID. To prevent the
case, it uses idr cyclic allocator same as kernel pid's.

Signed-off-by: Eric Huang <jinhuieric.huang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 8f1de51f49be692de137c8525106e0fce2d1912d)
Cc: stable@vger.kernel.org