BugLink: http://bugs.launchpad.net/bugs/1553179

commit ac4a9350 upstream.

DP audio is derived from the dfs clock.
Signed-off-by: Slava Grigorev <slava.grigorev@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>