There are AMDGPU_MAX_VMHUBS of vmhub in maximum and need to init the
vm_inv_engs for all of them.
In this way, the below error can be ruled out.
[ 217.317752] amdgpu 0000:02:00.0: amdgpu: no VM inv eng for ring sdma0
Signed-off-by: Shiwu Zhang <shiwu.zhang@amd.com> Reviewed-by: Christian Koenig <Christian.Koenig@amd.com> Reviewed-by: Le Ma <Le.Ma@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>