Add a new function drm_edid_connector_update() to replace the
combination of calls drm_connector_update_edid_property() and
drm_add_edid_modes(). Usually they are called in the drivers in this
order, however the former needs information from the latter.

Since the new drm_edid_read*() functions no longer call the connector
updates directly, and the read and update are separated, we'll need this
new function for the connector update.

This is all in drm_edid.c simply to keep struct drm_edid opaque.

v2:
- Share code with drm_connector_update_edid_property() (Ville)
- Add comment about override EDID handling

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/75aa3dbc8c9aa26ebbcdeacd98a466ef8d8827f4.1656494768.git.jani.nikula@intel.com