drm/amdkfd: Added Vega12 and Polaris12 for KFD.

Add Vega12 and Polaris12 device info and device IDs to KFD.

Signed-off-by: Gang Ba <gaba@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>