Fix dcbz too look at the BLLOADSIZE vs the SAB location

Change-Id: I0d88f5126cba9597098b86fc0ffa8b2e52ff6237
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/38177
Reviewed-by: Nicholas E. Bofferding <bofferdn@us.ibm.com>
Reviewed-by: Michael Baiocchi <mbaiocch@us.ibm.com>
Reviewed-by: Martin Gloff <mgloff@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: William G. Hoffa <wghoffa@us.ibm.com>

src/bootloader/bl_start.S

@@ -225,8 +225,8 @@ _main:
 
     ;// Do dcbz from end of Bootloader load to end of HBB ECC working space
 _dcbz_after_bl:
-    lis r5, SBE_HB_SECUREACCESSBIT@h
-    ori r5, r5, SBE_HB_SECUREACCESSBIT@l
+    lis r5, SBE_HB_BLLOADSIZE@h
+    ori r5, r5, SBE_HB_BLLOADSIZE@l
     ld r5, 0(r5)       ;// get ending EA from SBE HB structure
     lis r6, 0
     addis r6, r6, 32   ;// 2M (32 * 0x10000)