milenage_test: cosmetic fix: shown value is not SEQ.MS

In the milenage_test, the console output printed "SEQ.MS = 33", but 33 is
a) the SQN, not SEQ;
b) the SQN *after* the next auth generation, i.e. SQN.MS would have been 31.

While at it also use the proper PRIu64 from inttypes.h to output the sqn value.

This prepares for upcoming sparation of SQN incrementing by SEQ and IND,
particularly to clearly show where the changes in auth/milenage_test's
expectations originate.

Related: OS#1968
Change-Id: Ie83201f1362f3d793ada774f3fc5f89cc0b3fbb7
diff --git a/tests/auth/milenage_test.c b/tests/auth/milenage_test.c
index 473be92..187b9ad 100644
--- a/tests/auth/milenage_test.c
+++ b/tests/auth/milenage_test.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <errno.h>
 #include <string.h>
+#include <inttypes.h>
 
 #include <osmocom/crypt/auth.h>
 #include <osmocom/core/utils.h>
@@ -93,7 +94,8 @@
 	if (rc < 0) {
 		printf("AUTS failed\n");
 	} else {
-		printf("AUTS success: SEQ.MS = %llu\n", (unsigned long long)test_aud.u.umts.sqn);
+		printf("AUTS success: tuple generated with SQN = %" PRIu64 "\n",
+		       test_aud.u.umts.sqn);
 	}
 
 	opc_test(&test_aud);