drm/radeon: Clean up errors in radeon_audio.c

Fix the following errors reported by checkpatch:

ERROR: "foo* bar" should be "foo *bar"
ERROR: that open brace { should be on the previous line

Signed-off-by: GuoHua Chen <chenguohua_716@163.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>