meta-aspeed: prep for new override syntax

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I8135871ae0e3b360aff7d878f7cf04a2504f2dd0
diff --git a/meta-aspeed/classes/socsec-sign.bbclass b/meta-aspeed/classes/socsec-sign.bbclass
index 1b15765..b5866e2 100644
--- a/meta-aspeed/classes/socsec-sign.bbclass
+++ b/meta-aspeed/classes/socsec-sign.bbclass
@@ -59,7 +59,7 @@
 }
 
 
-do_deploy_append() {
+do_deploy:append() {
     if [ "${SOCSEC_SIGN_ENABLE}" = "1" -a -n "${SPL_BINARY}" ] ; then
         sign_spl
     fi