dist/jlink.sh: Allow overwriting the 'reset' commands
dist/jlink.sh: Allow overwriting the 'reset' commands

Add a variable to configure the reset commands.
This is required for board that need a hardware reset.

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