drm/radeon/kms: allow STRMOUT_BASE_UPDATE on RS780 and RS880

This is required to make streamout work there.

Signed-off-by: Marek Olšák <maraeo@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
2 files changed