RTC Story 37664 - Fix VBU fail in test_FSICOMreadWrite_centaur
RTC Story 37664 - Fix VBU fail in test_FSICOMreadWrite_centaur

The testcase was trying to set reserved bits in the scom register
which resulted in a data mismatch.  I limited the bits in the test.

Change-Id: Ia710caf41cab8bba0ad293a02803345c71e085ae
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/696
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <c87e37b1a4035affd737b461af89fb722d635f4d@us.ibm.com>
Reviewed-by: Van H. Lee <4779028c32a38a4c4983eb75cd78dd3e7dcc26f0@us.ibm.com>

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