treewide: support yocto kirkstone release

Add support for kirkstone without removing hardknott. After the rebase
we need remove hardknott manully.

Compatible with upstream change:
https://gerrit.openbmc-project.xyz/c/openbmc/openbmc/+/51576/

Signed-off-by: Hao Jiang <jianghao@google.com>
Change-Id: Ic791934cb155f8f5afd17b3c8f43ee5d7fa47cc8
diff --git a/conf/layer.conf b/conf/layer.conf
index dfe3e4f..9137996 100644
--- a/conf/layer.conf
+++ b/conf/layer.conf
@@ -9,5 +9,5 @@
 
 BBFILE_COLLECTIONS += "gbmc-staging-layer"
 BBFILE_PATTERN_gbmc-staging-layer := "^${LAYERDIR}/"
-LAYERSERIES_COMPAT_gbmc-staging-layer = "hardknott honister"
+LAYERSERIES_COMPAT_gbmc-staging-layer = "hardknott honister kirkstone"
 LAYERDEPENDS_gbmc-staging-layer += "google-layer"