Update garrison.config to unset DJVPD_WRITE_TO_HW

The RAS and system owners have determined that
we should not be saving bit repair information
permanently into the DIMM's SPD based on feedback
from other OpenPOWER systems. Instead we will
preserve the repairs inside the VPD cache only.
diff --git a/openpower/configs/hostboot/garrison.config b/openpower/configs/hostboot/garrison.config
index 4dd3cde..7fc9adf 100755
--- a/openpower/configs/hostboot/garrison.config
+++ b/openpower/configs/hostboot/garrison.config
@@ -11,7 +11,7 @@
 set MVPD_READ_FROM_PNOR
 set MVPD_WRITE_TO_PNOR
 set DJVPD_READ_FROM_HW
-set DJVPD_WRITE_TO_HW
+unset DJVPD_WRITE_TO_HW
 set DJVPD_READ_FROM_PNOR
 set DJVPD_WRITE_TO_PNOR
 set CVPD_READ_FROM_HW