drm/i915: Set hwmode during readout.
This was introduced after converting hw readout to atomic,
so it should have been part of the revert too.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90929
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>