usb: MAINTAINERS: Oliver Neukum is the new uas maintainer

Oliver Neukum is taking over uas maintainership from me and Gerd
Hoffmann.

Cc: Oliver Neukum <oneukum@suse.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Oliver Neukum <oneukum@suse.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>