drm/radeon: Assign VMID to PASID for IH in non-HWS mode

This patch fixes a bug in kgd_set_pasid_vmid_mapping(), where the function
only updated the ATC registers (IOMMU) with the new VMID <--> PASID mapping,
but didn't update the IH (Interrupt) registers.

The bug only occurs when using non-HWS mode. In HWS mode, the CP automatically
does the VMID <--> PASID mapping.

Signed-off-by: Ben Goz <ben.goz@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>