drm/radeon: check for 0 count in speaker allocation and SAD code

If there is no speaker allocation block or SAD block, bail
early.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=72283

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