meta-phosphor: migrate aspeed-layer to dynamic-layers

The proper way to add extensions to another layer is with
BBFILES_DYNAMIC rather than adding to BBFILES based on
BBFILE_COLLECTIONS.  Move aspeed-layer to a dynamic-layers subdirectory
and hook into layer.conf using BBFILES_DYNAMIC.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I26e5093d469ce0a57c0b93bcc6b3383dd7bcf264
diff --git a/meta-phosphor/conf/layer.conf b/meta-phosphor/conf/layer.conf
index 7e510ea..787b36d 100644
--- a/meta-phosphor/conf/layer.conf
+++ b/meta-phosphor/conf/layer.conf
@@ -19,3 +19,8 @@
 # Add layer-specific bb files too
 BBFILES += "${@' '.join('${LAYERDIR}/%s/recipes*/*/*.bb' % layer \
                for layer in BBFILE_COLLECTIONS.split())}"
+
+BBFILES_DYNAMIC += " \
+    aspeed-layer:${LAYERDIR}/dynamic-layers/aspeed-layer/recipes-*/*/*.bb \
+    aspeed-layer:${LAYERDIR}/dynamic-layers/aspeed-layer/recipes-*/*/*.bbappend \
+"