PRD: add mutex lock around Restore DRAM Repairs code
PRD: add mutex lock around Restore DRAM Repairs code

Change-Id: I8094134850e489e716163ae495633f0c8ba481c8
CQ: SW255802
Backport: release-fips810
Reviewed-on: http://gfw160.aus.stglabs.ibm.com:8080/gerrit/10181
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <c87e37b1a4035affd737b461af89fb722d635f4d@us.ibm.com>

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