Revert "linux: drm/radeon: use sw CTS/N values for audio on DCE4+"

Causes issues with 24p mode
Carefully watching: https://bugs.freedesktop.org/show_bug.cgi?id=69675 for future changes, especially when we upgrade to 3.12

This reverts commit 1deb6bd5a58755f4cc33a42bb3490104f9a7bdb6.