meta-ibm: prep for new override syntax

Change-Id: I9116ed7260e369136acb39eec15075db2d4dbeba
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-ibm/meta-palmetto/conf/machine/palmetto.conf b/meta-ibm/meta-palmetto/conf/machine/palmetto.conf
index 9e1c123..6f0e905 100644
--- a/meta-ibm/meta-palmetto/conf/machine/palmetto.conf
+++ b/meta-ibm/meta-palmetto/conf/machine/palmetto.conf
@@ -6,7 +6,7 @@
 require conf/machine/include/openpower.inc
 require conf/machine/include/p8.inc
 
-UBOOT_MACHINE_palmetto = "ast_g4_ncsi_config"
+UBOOT_MACHINE:palmetto = "ast_g4_ncsi_config"
 UBOOT_ENTRYPOINT = "0x40008000"
 UBOOT_LOADADDRESS = "0x40008000"