Since we want both horizontal and vertical resolution, just get both
with the same call.

Change-Id: I7b08b94e792b069b86e334608d6d6dc3901ad181
Reviewed-on: https://gerrit.libreoffice.org/11423Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>