Update hostboot-binaries Version in Config.in

The Config.in currently contains a version of hostboot-binaries that's too old. This commit updates the version to the latest version of hostboot-binaries so that automatic sync can be performed.
diff --git a/openpower/package/hostboot-binaries/Config.in b/openpower/package/hostboot-binaries/Config.in
index 44adc39..8660b2e 100644
--- a/openpower/package/hostboot-binaries/Config.in
+++ b/openpower/package/hostboot-binaries/Config.in
@@ -24,7 +24,7 @@
 
 config BR2_HOSTBOOT_BINARIES_VERSION
 	string
-	default "hw042221a.opmst10" if BR2_HOSTBOOT_BINARIES_LATEST_VERSION
+	default "hw061821a.opmst10" if BR2_HOSTBOOT_BINARIES_LATEST_VERSION
 	default BR2_HOSTBOOT_BINARIES_CUSTOM_VERSION_VALUE \
 		if BR2_HOSTBOOT_BINARIES_CUSTOM_VERSION