Merge pull request #3903 from opalci/skiboot-v6.6.4

skiboot v6.6.4
diff --git a/openpower/package/skiboot/Config.in b/openpower/package/skiboot/Config.in
index f9e108c..c7c37e7 100644
--- a/openpower/package/skiboot/Config.in
+++ b/openpower/package/skiboot/Config.in
@@ -31,7 +31,7 @@
 
 config BR2_SKIBOOT_VERSION
 	string
-	default "v6.6.3" if BR2_SKIBOOT_LATEST_VERSION
+	default "v6.6.4" if BR2_SKIBOOT_LATEST_VERSION
 	default BR2_SKIBOOT_CUSTOM_VERSION_VALUE \
 		if BR2_SKIBOOT_CUSTOM_VERSION