drm/radeon: fix N/CTS clock matching for audio

commit e7d12c2f98ae1e68c7298e5028048d150fa553a1 upstream.

The drm code that calculates the 1001 clocks rounds up
rather than truncating.  This allows the table to match
properly on those modes.

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



Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>