Make sure SSI0 is powered and clocked before accessing it
Make sure SSI0 is powered and clocked before accessing it

* Fail all SSI0 operations if the module is not powered and clocked
* Make sure SERIAL is powered before trying to enable run mode clock

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