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: If6dce81faee9177737a6e1b572a871aaf7e37138
diff --git a/src/osmo-bsc_nat/bsc_nat_utils.c b/src/osmo-bsc_nat/bsc_nat_utils.c
index a9906b9..3094bbd 100644
--- a/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -206,7 +206,7 @@
 	llist_del(&cfg->entry);
 	rate_ctr_group_free(cfg->stats.ctrg);
 	cfg->nat->num_bsc--;
-	OSMO_ASSERT(cfg->nat->num_bsc >= 0)
+	OSMO_ASSERT(cfg->nat->num_bsc >= 0);
 	talloc_free(cfg);
 }