Update genHwsvMrwXml.pl for p9_io_xbus_attributes.xml default values
Update genHwsvMrwXml.pl for p9_io_xbus_attributes.xml default values

Change-Id: I554f31f81b6ed1c52e8828b398d7c8b7f1e8644f
RTC: 161062
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/30570
Tested-by: Jenkins Server <8e3f934e4c44875bc48d33da3ea13d93ba9a233f@us.ibm.com>
Tested-by: FSP CI Jenkins <aa9e4d9ac7cd25905e9c0dd36d4150516e73dd86@us.ibm.com>
Reviewed-by: Christian R. Geddes <f397583a9caa8163a06ad1128784fb67413f2fe6@us.ibm.com>
Reviewed-by: Daniel M. Crowell <912029ca9254ac7b5854e56910561d682e1fa2d0@us.ibm.com>

Over-enthusiastic/hostboot,Over-enthusiastic/hostboot,Over-enthusiastic/hostboot,Over-enthusiastic/hostboot,Over-enthusiastic/hostboot