Add ability to force all subpackage version strings to be generated

Originally openpower-pnor-version would only end up rebuilding
subpackages that don't have a version file, even if outdated.
diff --git a/openpower/package/pkg-versions.mk b/openpower/package/pkg-versions.mk
index 3ac8c9f..e3acbda 100644
--- a/openpower/package/pkg-versions.mk
+++ b/openpower/package/pkg-versions.mk
@@ -184,7 +184,6 @@
 		@cat $$($$(UPPER_CASE_PKG)_VERSION_FILE)
 		@echo ""; echo "**See openpower/package/VERSION.readme for detailed info on package strings"; echo ""
 
-
 # Rule to generate pnor version
 $(1)-build-version: $$(foreach pkg,$$(OPENPOWER_VERSIONED_SUBPACKAGES), $$(pkg)-version)
 		@$$($$(UPPER_CASE_PKG)_OPENPOWER_VERSION_FILE)
@@ -192,4 +191,11 @@
 		@cat $$($$(UPPER_CASE_PKG)_VERSION_FILE)
 		@echo ""; echo "**See openpower/package/VERSION.readme for detailed info on package strings"; echo ""
 
+# Rule to force re-generation of all versioned subpackages
+$(1)-build-version-all: $$(foreach pkg,$$(OPENPOWER_VERSIONED_SUBPACKAGES), $$(pkg)-build-version)
+		@$$($$(UPPER_CASE_PKG)_OPENPOWER_VERSION_FILE)
+		@echo "=== $$(UPPER_CASE_PKG)_VERSION ==="
+		@cat $$($$(UPPER_CASE_PKG)_VERSION_FILE)
+		@echo ""; echo "**See openpower/package/VERSION.readme for detailed info on package strings"; echo ""
+
 endef