tests/nimble_l2cap: fix type passing AD to bluetil
tests/nimble_l2cap: fix type passing AD to bluetil

OTAkeys/RIOT,yogo1212/RIOT,kaspar030/RIOT,miri64/RIOT,ant9000/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,basilfx/RIOT,RIOT-OS/RIOT,toonst/RIOT,kYc0o/RIOT,basilfx/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,smlng/RIOT,toonst/RIOT,OlegHahm/RIOT,jasonatran/RIOT,authmillenon/RIOT,OTAkeys/RIOT,yogo1212/RIOT,josephnoir/RIOT,ant9000/RIOT,OTAkeys/RIOT,kaspar030/RIOT,basilfx/RIOT,RIOT-OS/RIOT,miri64/RIOT,x3ro/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,jasonatran/RIOT,mtausig/RIOT,x3ro/RIOT,smlng/RIOT,jasonatran/RIOT,basilfx/RIOT,authmillenon/RIOT,kaspar030/RIOT,kYc0o/RIOT,yogo1212/RIOT,authmillenon/RIOT,jasonatran/RIOT,smlng/RIOT,authmillenon/RIOT,OlegHahm/RIOT,ant9000/RIOT,kaspar030/RIOT,miri64/RIOT,jasonatran/RIOT,kYc0o/RIOT,x3ro/RIOT,mtausig/RIOT,josephnoir/RIOT,miri64/RIOT,mtausig/RIOT,authmillenon/RIOT,x3ro/RIOT,basilfx/RIOT,josephnoir/RIOT,authmillenon/RIOT,toonst/RIOT,kaspar030/RIOT,OlegHahm/RIOT,toonst/RIOT,smlng/RIOT,smlng/RIOT,ant9000/RIOT,yogo1212/RIOT,josephnoir/RIOT,kYc0o/RIOT,yogo1212/RIOT,josephnoir/RIOT,toonst/RIOT,miri64/RIOT,kYc0o/RIOT,mtausig/RIOT,ant9000/RIOT,x3ro/RIOT,OTAkeys/RIOT,OlegHahm/RIOT,mtausig/RIOT