Update Sim Startup Script to find master CPU dynamically
Update Sim Startup Script to find master CPU dynamically

   - Previously a hardcoded object name was used, need to use
     the get-master-cpus function

Change-Id: I03c1a686e577e9465d9ca138140eae2e5b5ec286
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/88111
Reviewed-by: Ilya Smirnov <2c7a6ec38cfb553b896499595cca9c656159f2a4@us.ibm.com>
Reviewed-by: Christian R Geddes <f397583a9caa8163a06ad1128784fb67413f2fe6@us.ibm.com>
Reviewed-by: Nicholas E Bofferding <fb8db48116bc8a69e29dd8cdb037246f232f4af5@us.ibm.com>
Tested-by: Jenkins Server <8e3f934e4c44875bc48d33da3ea13d93ba9a233f@us.ibm.com>
Tested-by: Jenkins OP Build CI <e610bd72261d3c0a48f1e8ae36832ab00774d426@us.ibm.com>

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