boards/yunjia-nrf51822: add missing I2C speed config
boards/yunjia-nrf51822: add missing I2C speed config

gebart/RIOT,OTAkeys/RIOT,josephnoir/RIOT,josephnoir/RIOT,toonst/RIOT,BytesGalore/RIOT,mfrey/RIOT,toonst/RIOT,OlegHahm/RIOT,toonst/RIOT,gebart/RIOT,jasonatran/RIOT,josephnoir/RIOT,authmillenon/RIOT,yogo1212/RIOT,ant9000/RIOT,kaspar030/RIOT,x3ro/RIOT,cladmi/RIOT,kYc0o/RIOT,ant9000/RIOT,cladmi/RIOT,mfrey/RIOT,yogo1212/RIOT,biboc/RIOT,OlegHahm/RIOT,gebart/RIOT,yogo1212/RIOT,rfuentess/RIOT,BytesGalore/RIOT,BytesGalore/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,mtausig/RIOT,mtausig/RIOT,mfrey/RIOT,lazytech-org/RIOT,x3ro/RIOT,OTAkeys/RIOT,rfuentess/RIOT,basilfx/RIOT,OTAkeys/RIOT,avmelnikoff/RIOT,basilfx/RIOT,A-Paul/RIOT,smlng/RIOT,yogo1212/RIOT,aeneby/RIOT,avmelnikoff/RIOT,x3ro/RIOT,mtausig/RIOT,authmillenon/RIOT,avmelnikoff/RIOT,cladmi/RIOT,toonst/RIOT,yogo1212/RIOT,kYc0o/RIOT,x3ro/RIOT,rfuentess/RIOT,kaspar030/RIOT,miri64/RIOT,mtausig/RIOT,basilfx/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,kbumsik/RIOT,josephnoir/RIOT,lazytech-org/RIOT,mfrey/RIOT,avmelnikoff/RIOT,gebart/RIOT,OlegHahm/RIOT,kbumsik/RIOT,cladmi/RIOT,OTAkeys/RIOT,mtausig/RIOT,mfrey/RIOT,basilfx/RIOT,cladmi/RIOT,kYc0o/RIOT,smlng/RIOT,gebart/RIOT,aeneby/RIOT,kaspar030/RIOT,ant9000/RIOT,kbumsik/RIOT,authmillenon/RIOT,ant9000/RIOT,aeneby/RIOT,miri64/RIOT,rfuentess/RIOT,ant9000/RIOT,OTAkeys/RIOT,smlng/RIOT,kaspar030/RIOT,kaspar030/RIOT,lazytech-org/RIOT,miri64/RIOT,A-Paul/RIOT,jasonatran/RIOT,yogo1212/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,A-Paul/RIOT,rfuentess/RIOT,lazytech-org/RIOT,jasonatran/RIOT,kYc0o/RIOT,authmillenon/RIOT,jasonatran/RIOT,BytesGalore/RIOT,RIOT-OS/RIOT,smlng/RIOT,avmelnikoff/RIOT,OlegHahm/RIOT,biboc/RIOT,BytesGalore/RIOT,basilfx/RIOT,authmillenon/RIOT,smlng/RIOT,kbumsik/RIOT,biboc/RIOT,A-Paul/RIOT,A-Paul/RIOT,josephnoir/RIOT,kbumsik/RIOT,biboc/RIOT,x3ro/RIOT,aeneby/RIOT,aeneby/RIOT,lazytech-org/RIOT,miri64/RIOT,toonst/RIOT,miri64/RIOT,biboc/RIOT,RIOT-OS/RIOT,jasonatran/RIOT