drm/radeon: add Richland pci ids

commit b75bbaa038ffc426e88ea3df6c4ae11834fc3e4f upstream.

Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>