fixed clock_seconds to use full 32 bit
fixed clock_seconds to use full 32 bit

MohamedSeliem/contiki,bluerover/6lbr,arurke/contiki,arurke/contiki,MohamedSeliem/contiki,arurke/contiki,bluerover/6lbr,arurke/contiki,arurke/contiki,bluerover/6lbr,arurke/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,bluerover/6lbr,MohamedSeliem/contiki,MohamedSeliem/contiki,bluerover/6lbr,bluerover/6lbr,bluerover/6lbr,arurke/contiki