retro-input-manager: Don't set default joypad controller

Rely on joypad controller on a specific port instead. This allows to
avoid the same input on every port, controlling multiple players at once
on some platforms.
6 jobs for wip/exalm/keyboard in 25 minutes and 58 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
passed flatpak:app #157925

00:14:35

 
  Test
passed flatpak:tests #157926

00:03:30

 
  Review
passed review #157927

00:00:23

passed stop_review #157928
manual

00:00:25

 
  Cross Distro
passed fedora:29 #157929

00:03:22

passed ubuntu:devel #157930

00:07:03