BugLink: http://bugs.launchpad.net/bugs/1573034

commit 0e5585dc upstream.

Higher mclk values are not stable due to a bug somewhere.
Limit them for now.
Signed-off-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>