drm/radeon: only enable audio streams if the monitor supports it

Selectively enable which packets we send based on monitor caps.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --cc drivers/gpu/drm/radeon/atombios_encoders.c
Simple merge

diff --cc drivers/gpu/drm/radeon/evergreen_hdmi.c
Simple merge