BugLink: http://bugs.launchpad.net/bugs/1638267

commit 42792029 upstream.

Used the wrong index to setup the phase shedding mask.
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>