addflags: change type of integer argument to uint64_t

This is necessary for the upcoming change of xlat.val type.
All users of addflags are already prepared for this change.

* defs.h (addflags): Change type of integer argument to uint64_t.
* util.c (addflags): Likewise.  Print it using PRIx64 format.
Based on patch by Jeff Mahoney <jeffm@suse.com>.
diff --git a/util.c b/util.c
index 1e5aecc..763fd11 100644
--- a/util.c
+++ b/util.c
@@ -303,7 +303,7 @@
  * return # of flags printed.
  */
 void
-addflags(const struct xlat *xlat, int flags)
+addflags(const struct xlat *xlat, uint64_t flags)
 {
 	for (; xlat->str; xlat++) {
 		if (xlat->val && (flags & xlat->val) == xlat->val) {
@@ -312,7 +312,7 @@
 		}
 	}
 	if (flags) {
-		tprintf("|%#x", flags);
+		tprintf("|%#" PRIx64, flags);
 	}
 }