Fix potential NULL pointer dereference
Fix potential NULL pointer dereference

Safety check...

Signed-off-by: Ananth N Mavinakayanahalli <7dc108d19a2513f6455353af182b9e4d3b794ec9@in.ibm.com>
Reviewed-by: Vasant Hegde <a6d753843573f7bfed5075c1e875b0be8007a0ab@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

stewart-ibm/skiboot,stewart-ibm/skiboot,open-power/skiboot,legoater/skiboot,legoater/skiboot,open-power/skiboot,legoater/skiboot,apopple/skiboot,apopple/skiboot,qemu/skiboot,qemu/skiboot,ddstreet/skiboot,qemu/skiboot,legoater/skiboot,open-power/skiboot,qemu/skiboot,legoater/skiboot,csmart/skiboot,csmart/skiboot,shenki/skiboot,shenki/skiboot,mikey/skiboot,mikey/skiboot,mikey/skiboot,csmart/skiboot,shenki/skiboot,open-power/skiboot,shenki/skiboot,open-power/skiboot,shenki/skiboot,stewart-ibm/skiboot,ddstreet/skiboot,qemu/skiboot,ddstreet/skiboot,apopple/skiboot