orangefs: turn param response value into union

This will support a upcoming request where two related values need to be
updated atomically.

This was done without a union in the OrangeFS server source already. Since
that will break the kernel protocol, it has been fixed there and done here
in a way that does not break the kernel protocol.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
diff --git a/fs/orangefs/upcall.h b/fs/orangefs/upcall.h
index 03a4360..7c29fdf 100644
--- a/fs/orangefs/upcall.h
+++ b/fs/orangefs/upcall.h
@@ -187,7 +187,10 @@
 struct orangefs_param_request_s {
 	enum orangefs_param_request_type type;
 	enum orangefs_param_request_op op;
-	__s64 value;
+	union {
+		__s64 value64;
+		__s32 value32[2];
+	} u;
 	char s_value[ORANGEFS_MAX_DEBUG_STRING_LEN];
 };