add ';' after OSMO_ASSERT()

Currently, OSMO_ASSERT() is defined such that it ends in a semicolon, hence an
added ';' is redundant. However, the usual way this kind of macro should be
defined is

  #define OSMO_ASSERT(x) do { ... } while(0)

so that the compiler requires a trailing semicolon.

To prepare for such a change possibly coming up in libosmocore, add ';' to all
OSMO_ASSERT() users.

Change-Id: Ic79c8b8f98a7f3bef761751d55a7e6125cf2c46d

src/libmsc/gsm_04_08.c

@@ -3220,7 +3220,7 @@ int gsm0408_dispatch(struct gsm_subscriber_connection *conn, struct msgb *msg)
 	uint8_t pdisc;
 	int rc = 0;
 
-	OSMO_ASSERT(msg->l3h)
+	OSMO_ASSERT(msg->l3h);
 	OSMO_ASSERT(conn);
 	OSMO_ASSERT(msg);