p9_revert_sbe_mcs_setup - Fix incorrect unmask reg addr

revert_mcs_hb_dcbz_config()  is writing to the absolute
address for the MCS0 FIR mask address against a chip
target, which is not guaranteed to exist.
Change it to use the address appropriate for the passed
in MCS instance.

Change-Id: Icf9e4c0198aad554e991addf85592208830703e3
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/37256
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Hostboot CI <hostboot-ci+hostboot@us.ibm.com>
Reviewed-by: Benjamin Gass <bgass@us.ibm.com>
Reviewed-by: Joseph J. McGill <jmcgill@us.ibm.com>
Reviewed-by: Jennifer A. Stofer <stofer@us.ibm.com>
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/37259
Reviewed-by: Hostboot Team <hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

src/import/chips/p9/procedures/hwp/nest/p9_revert_sbe_mcs_setup.C

@@ -137,8 +137,8 @@ revert_mcs_hb_dcbz_config(const fapi2::Target<fapi2::TARGET_TYPE_PROC_CHIP>& i_t
         // Re-mask MCFIR. We want to ensure all MCSs are masked
         // until the BARs are opened later during IPL.
         l_mcfirmask.flush<1>();
-        FAPI_TRY(fapi2::putScom(i_target, MCS_MCFIRMASK, l_mcfirmask),
-                 "Error from putScom (MCS_MCFIRMASK)");
+        FAPI_TRY(fapi2::putScom(i_target, MCS_MCFIRMASK_OR_ARR[i_mcs], l_mcfirmask),
+                 "Error from putScom (MCS%d_MCFIRMASK_OR)", i_mcs);
     }
 
 fapi_try_exit: