meta-evb: Fix warnings

 WARNING: Layer evb should set LAYERSERIES_COMPAT_evb in its
 conf/layer.conf file to list the core layer names it is compatible
 with.

 WARNING: Layer evb-aspeed should set LAYERSERIES_COMPAT_evb-aspeed in
 its conf/layer.conf file to list the core layer names it is compatible
 with.

 WARNING: Layer evb-ast2500 should set LAYERSERIES_COMPAT_evb-ast2500 in
 its conf/layer.conf file to list the core layer names it is compatible
 with.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Change-Id: I1835b6ed28e4e2d77aadbe6f328001a3ce6e68ce
diff --git a/meta-evb/meta-evb-aspeed/conf/layer.conf b/meta-evb/meta-evb-aspeed/conf/layer.conf
index 369f84d..9a36f2e 100644
--- a/meta-evb/meta-evb-aspeed/conf/layer.conf
+++ b/meta-evb/meta-evb-aspeed/conf/layer.conf
@@ -4,4 +4,4 @@
 BBFILE_COLLECTIONS += "evb-aspeed"
 BBFILE_PATTERN_evb-aspeed = ""
 
-LAYERSERIES_COMPAT_evb-aspeed-layer = "honister kirkstone"
+LAYERSERIES_COMPAT_evb-aspeed = "honister kirkstone"