tests/suit_manifest: increase timeout for nrf51dk
tests/suit_manifest: increase timeout for nrf51dk

OlegHahm/RIOT,kYc0o/RIOT,authmillenon/RIOT,jasonatran/RIOT,miri64/RIOT,OTAkeys/RIOT,authmillenon/RIOT,OlegHahm/RIOT,authmillenon/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,miri64/RIOT,authmillenon/RIOT,kaspar030/RIOT,ant9000/RIOT,kYc0o/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,miri64/RIOT,OlegHahm/RIOT,ant9000/RIOT,jasonatran/RIOT,miri64/RIOT,OlegHahm/RIOT,kaspar030/RIOT,kaspar030/RIOT,jasonatran/RIOT,OlegHahm/RIOT,kaspar030/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,ant9000/RIOT,kYc0o/RIOT,ant9000/RIOT,kaspar030/RIOT,authmillenon/RIOT,kYc0o/RIOT,authmillenon/RIOT,OTAkeys/RIOT,miri64/RIOT,RIOT-OS/RIOT,ant9000/RIOT,kYc0o/RIOT,RIOT-OS/RIOT