Fix const-correctness bug in std::map splay tree implementation
Fix const-correctness bug in std::map splay tree implementation

Code that uses std::map::find on a reference to a constant map in order
to get a const_iterator fails due to a missing const in the underlying
splay tree implementation. This is Patrick's fix!

Change-Id: Ifcf65b097f55a635d24774c81fdbf380e9058943
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/1234
Reviewed-by: Mark W. Wenning <32e1305d9513301b64a3e92b63a7c80399d0fb59@us.ibm.com>
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <c87e37b1a4035affd737b461af89fb722d635f4d@us.ibm.com>

open-power/hostboot,alvintpwang/hostboot,open-power/hostboot,alvintpwang/hostboot,Over-enthusiastic/hostboot,Over-enthusiastic/hostboot,alvintpwang/hostboot,alvintpwang/hostboot,open-power/hostboot,csmart/hostboot,csmart/hostboot,csmart/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,Over-enthusiastic/hostboot,csmart/hostboot,Over-enthusiastic/hostboot,alvintpwang/hostboot,open-power/hostboot,csmart/hostboot