drm/amdkfd: Fix Incorrect VMIDs passed to HWS

[ Upstream commit b7dfbd2e601f3fee545bc158feceba4f340fe7cf ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>