drm/i915: Nuke dev_priv->drrs.type

drm/i915: Nuke dev_priv->drrs.type

When we found a downclock mode dev_priv->drrs.type is just a
straight copy of dev_priv->vbt.drrs_type. And in case we
couldn't find a downclock mode can_enable_drrs() won't let
us enable DRRS anyway so the minor distinction between the
two is irrelevant. So let's just nuke dev_priv->drrs.type
and consult the VBT version directly.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220311172428.14685-6-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>