Merge pull request #578 from stewart-ibm/bump-skiboot-5.3.1

Bump skiboot to 5.3.1
diff --git a/openpower/package/skiboot/Config.in b/openpower/package/skiboot/Config.in
index 551c81b..ca766f9 100644
--- a/openpower/package/skiboot/Config.in
+++ b/openpower/package/skiboot/Config.in
@@ -31,7 +31,7 @@
 
 config BR2_SKIBOOT_VERSION
 	string
-	default "skiboot-5.3.0" if BR2_SKIBOOT_LATEST_VERSION
+	default "skiboot-5.3.1" if BR2_SKIBOOT_LATEST_VERSION
 	default BR2_SKIBOOT_CUSTOM_VERSION_VALUE \
 		if BR2_SKIBOOT_CUSTOM_VERSION