models.json: add buffalo-wzr-hp-ag300h-wzr-600dhp
models.json: add buffalo-wzr-hp-ag300h-wzr-600dhp

freifunk-darmstadt/ffda-firmware-splash,Freifunk-Rhein-Neckar/ffda-firmware-splash,freifunk-darmstadt/ffda-firmware-splash,Freifunk-Rhein-Neckar/ffda-firmware-splash