drm/amdgpu: add userq specific kernel config for fence ioctls

Keep the user queue fence signal and wait IOCTLs in the
kernel config CONFIG_DRM_AMDGPU_NAVI3X_USERQ.

v2(Christian):
  - Remove the userq specific config added for kernel queues fence init
    function.

v3(Alex):
  - It will be better to return an error(-ENOTSUPP) in these cases.

Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>