meta-nuvoton: layer.conf: Add warrior compatibility

oe-core branched in preparation for the upcoming 2.7 Yocto release and
as of 13e45ff requires core layer compatibility to "warrior" instead of
"thud".  We'll retain compatibility for both until we do our own branch
or stop testing thud.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: Ia726b28a67023e1528a6dc79476201aa579f3de6
diff --git a/conf/layer.conf b/conf/layer.conf
index 8c5d9d8..a592301 100644
--- a/conf/layer.conf
+++ b/conf/layer.conf
@@ -7,4 +7,4 @@
 BBFILE_COLLECTIONS += "nuvoton-layer"
 BBFILE_PATTERN_nuvoton-layer = ""
 LAYERVERSION_nuvoton-layer = "1"
-LAYERSERIES_COMPAT_nuvoton-layer = "thud"
+LAYERSERIES_COMPAT_nuvoton-layer = "thud warrior"