drm/amdkfd: Vega20 bring up on amdkfd side

Add Vega20 device IDs, device info and enable it in KFD.

Signed-off-by: Shaoyun Liu <Shaoyun.Liu@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>