set default length of bits to clear to one
set default length of bits to clear to one

Change-Id: I156e8dbaf28058672c99d208881b74ea267b440d
Reviewed-on: http://gfw160.aus.stglabs.ibm.com:8080/gerrit/20369
Tested-by: Jenkins Server
Reviewed-by: Brian Silver <af0eed78d989d9597decc8b92fa6db01ef8b58e0@us.ibm.com>
Reviewed-by: Richard J. Knight <94c04f3910596886be97211d492ad29f0ba29cd5@us.ibm.com>
Reviewed-by: Jennifer A. Stofer <ab93eca12e43608f33daa16a67357cd7b7e867ab@us.ibm.com>

open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot