pkg/semtech-loramac: update documentation with persistence mecanism
pkg/semtech-loramac: update documentation with persistence mecanism

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