drm/radeon: use 64-bit math to calculate CTS values for audio (v2)

Avoid losing precision.  See bug:
https://bugs.freedesktop.org/show_bug.cgi?id=69675

v2: fix math as per Anssi's comments.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed