drm/i915: Do not free the passed EDID in intel_connector_update_modes()

The caller, not intel_connector_update_modes(), should free the edid. This
improves the reusability of intel_connector_update_modes().

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>