drm/amdgpu: fix and cleanup gmc_v11_0_flush_gpu_tlb_pasid

The same PASID can be used by more than one VMID, reset each of them.

Use the common KIQ handling.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>