Create User Account profile creates error Undefined index: location_type_id in CRM_Dedupe_BAO_Rule
Since you talk about /user/register (which is not a drupal webform but a core drupal form) then this should be a Civi Profile and that is where you would edit the Location Type.

Your screenshot shows you have a Profile called "Name and Home Address" - 

have a look for 'edit' on one of the fields in the Profile eg 'Street' and there you should be able to specify the location type of 'street'