Compute-only GPUs have more than 8 VMIDs allocated to KFD. Fix
this by passing correct number of VMIDs to HWS

v2: squash in warning fix (Alex)
Signed-off-by: Tushar Patel <tushar.patel@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>