drm/amdgpu: explicitely sync to VM updates v2

Allows us to reduce the overhead while syncing to fences a bit.

v2: also drop adev parameter from the functions

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>