hardknott: yocto release

Latest upstream yocto has moved on to the 3.3 hardknott release

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: Ieae36798d66d21c2c642931f06407d3bb2acf163
diff --git a/meta-evb/meta-evb-aspeed/meta-evb-ast2600/conf/layer.conf b/meta-evb/meta-evb-aspeed/meta-evb-ast2600/conf/layer.conf
index 2a88b8a..75861bf 100644
--- a/meta-evb/meta-evb-aspeed/meta-evb-ast2600/conf/layer.conf
+++ b/meta-evb/meta-evb-aspeed/meta-evb-ast2600/conf/layer.conf
@@ -8,4 +8,4 @@
 BBFILE_COLLECTIONS += "meta-evb-ast2600"
 BBFILE_PATTERN_meta-evb-ast2600 = "^${LAYERDIR}/"
 
-LAYERSERIES_COMPAT_meta-evb-ast2600 = "dunfell gatesgarth"
+LAYERSERIES_COMPAT_meta-evb-ast2600 = "gatesgarth hardknott"