Fix start address logic for Populating HBRT data

Change-Id: I479af2a65d6085d9c482ca1bddf8647441282fea
CQ: SW392121
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/41828
Reviewed-by: Dean Sanner <dsanner@us.ibm.com>
Reviewed-by: Prachi Gupta <pragupta@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+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/usr/runtime/populate_hbruntime.C

@@ -683,7 +683,7 @@ errlHndl_t fill_RsvMem_hbData(uint64_t & io_start_address,
         }
         else
         {
-            io_start_address = io_end_address - l_totalSizeAligned + 1;
+            io_start_address = io_end_address - l_totalSizeAligned;
         }