Add openPOWER version string support

See VERSION.readme for more info
diff --git a/openpower/external.mk b/openpower/external.mk
index be628ba..8d7b578 100644
--- a/openpower/external.mk
+++ b/openpower/external.mk
@@ -1,5 +1,6 @@
+include $(sort $(wildcard $(BR2_EXTERNAL)/package/*.mk))
 include $(sort $(wildcard $(BR2_EXTERNAL)/package/*/*.mk))
 
 # Utilize user-defined custom directory.
 include $(sort $(wildcard $(BR2_EXTERNAL)/custom/*.mk))
-BR2_GLOBAL_PATCH_DIR += " $(BR2_EXTERNAL)/custom/patches "
+BR2_GLOBAL_PATCH_DIR += "$(BR2_EXTERNAL)/custom/patches"