meta-quanta: gbs: Add explicit layer dependencies

We want the machine layer to be guaranteed to override our top-level
layers.

Change-Id: Ib071dad5b43c112d729bf7f85f36a9f6bd571b31
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meta-quanta/meta-gbs/conf/layer.conf b/meta-quanta/meta-gbs/conf/layer.conf
index 9f41e05..cd2ca1d 100644
--- a/meta-quanta/meta-gbs/conf/layer.conf
+++ b/meta-quanta/meta-gbs/conf/layer.conf
@@ -8,3 +8,4 @@
 BBFILE_COLLECTIONS += "gbs-layer"
 BBFILE_PATTERN_gbs-layer := "^${LAYERDIR}/"
 LAYERSERIES_COMPAT_gbs-layer = "hardknott honister"
+LAYERDEPENDS_gbs-layer = "core phosphor-layer google-layer quanta-layer"