drm/i915: Move power well init earlier during driver load

intel_modeset_init() will already attempt to disable VGA. In order to do
that, it needs the power well to be on. So move the power well init
to happen before intel_modeset_init() during driver load.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>