Clear OPB Errors before starting FSI Init
Clear OPB Errors before starting FSI Init

Some systems seem to power on with OPB Overrun errors.  Added
code to clear out the OPB status regs before doing anything else.

Change-Id: I583fcb0964a7754f3fb6c558d528cbacc1e50714
CQ: SW210986
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/5136
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <c87e37b1a4035affd737b461af89fb722d635f4d@us.ibm.com>

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