Openmote-cc2538: format flash start address as hex
Openmote-cc2538: format flash start address as hex

Declaring the address in decimal format meant that it was being
interpreted as a decimal rather than hex address by the tooling
and the intermediate bash arithmetic. This fixes that bug.

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