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-arm/conf/layer.conf b/meta-arm/conf/layer.conf
index d031125..d111b24 100644
--- a/meta-arm/conf/layer.conf
+++ b/meta-arm/conf/layer.conf
@@ -9,4 +9,4 @@
 BBFILE_PATTERN_arm = "^${LAYERDIR}/"
 LAYERVERSION_arm = "1"
 
-LAYERSERIES_COMPAT_arm = "dunfell gatesgarth"
+LAYERSERIES_COMPAT_arm = "gatesgarth hardknott"