Introduce printxval64 wrapper

This is necessary for the upcoming change of xlat.val type.

* defs.h (printxval64): New static inline function.
diff --git a/defs.h b/defs.h
index 583f715..2cd2397 100644
--- a/defs.h
+++ b/defs.h
@@ -667,6 +667,12 @@
 #endif
 
 static inline void
+printxval64(const struct xlat *x, const uint64_t val, const char *dflt)
+{
+	printxvals(val, dflt, x, NULL);
+}
+
+static inline void
 printxval(const struct xlat *x, const unsigned int val, const char *dflt)
 {
 	printxvals(val, dflt, x, NULL);