We may only start to set up the new register values after having
confirmed that the ring is truely off. Otherwise the hw might lose the
newly written register values. This is caught later on in the init
sequence, when we check whether the register writes have stuck.

Cc: stable@vger.kernel.org
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=50522Tested-by: NYang Guang <guang.a.yang@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>