drm/i915: Move all ring resets before setting the HWS page

In commit a51435a3
Author: Naresh Kumar Kachhi <naresh.kumar.kachhi@intel.com>
Date:   Wed Mar 12 16:39:40 2014 +0530

    drm/i915: disable rings before HW status page setup

we reordered stopping the rings to do so before we set the HWS register.
However, there is an extra workaround for g45 to reset the rings twice,
and for consistency we should apply that workaround before setting the
HWS to be sure that the rings are truly stopped.

Reference: http://lkml.kernel.org/r/20140423202248.GA3621@amd.pavel.ucw.cz


Tested-by: Pavel Machek <pavel@ucw.cz>
Cc: Naresh Kumar Kachhi <naresh.kumar.kachhi@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>