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-phosphor/conf/layer.conf b/meta-phosphor/conf/layer.conf
index 2292acc..f651b2d 100644
--- a/meta-phosphor/conf/layer.conf
+++ b/meta-phosphor/conf/layer.conf
@@ -8,7 +8,7 @@
 BBFILE_COLLECTIONS += "phosphor-layer"
 BBFILE_PATTERN_phosphor-layer := "^${LAYERDIR}/"
 LAYERVERSION_phosphor-layer = "1"
-LAYERSERIES_COMPAT_phosphor-layer = "dunfell gatesgarth"
+LAYERSERIES_COMPAT_phosphor-layer = "gatesgarth hardknott"
 
 IMAGE_FEATURES[validitems] += "tools-profile"