drm/amdgpu: Alloc page table on correct memory partition

Alloc kernel mode page table bo uses the amdgpu_vm->mem_id + 1 as bp
mem_id_plus1 parameter. For APU mode, select the correct TTM pool to
alloc page from the corresponding memory partition, this will be the
closest NUMA node. For dGPU mode, select the correct address range for
vram manager.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>