Fix i2c bug in sensortag flatform.
Fix i2c bug in sensortag flatform.

arurke/contiki,arurke/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,arurke/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,arurke/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,arurke/contiki,arurke/contiki,arurke/contiki