utils.h: require a semi colon after OSMO_ASSERT

When using `OSMO_ASSERT(exp);` clang will warn about
an empty expression because the semi colon was superflous.
Use do {} while (0) to enfore the need of a semi colon.
This might break other test.

Change-Id: I2272d29a81496164bebd1696a694383a28a86434
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c
index afff59a..364a04f 100644
--- a/src/gsm/gsm0808_utils.c
+++ b/src/gsm/gsm0808_utils.c
@@ -273,7 +273,7 @@
 	case GSM0808_SCT_FR5:
 	case GSM0808_SCT_HR4:
 	case GSM0808_SCT_CSD:
-		OSMO_ASSERT((sc->cfg & 0xff00) == 0)
+		OSMO_ASSERT((sc->cfg & 0xff00) == 0);
 		msgb_put_u8(msg, (uint8_t) sc->cfg & 0xff);
 		break;
 	default:
@@ -874,7 +874,7 @@
 
 	msgb_put_u8(msg, cil->id_discr & 0x0f);
 
-	OSMO_ASSERT(cil->id_list_len <= GSM0808_CELL_ID_LIST2_MAXLEN)
+	OSMO_ASSERT(cil->id_list_len <= GSM0808_CELL_ID_LIST2_MAXLEN);
 	for (i = 0; i < cil->id_list_len; i++)
 		gsm0808_msgb_put_cell_id_u(msg, cil->id_discr, &cil->id_list[i]);
 
@@ -906,7 +906,7 @@
 
 	switch (cil->id_discr) {
 	case CELL_IDENT_LAC:
-		OSMO_ASSERT(cil->id_list_len <= CELL_ID_LIST_LAC_MAXLEN)
+		OSMO_ASSERT(cil->id_list_len <= CELL_ID_LIST_LAC_MAXLEN);
 		for (i=0;i<cil->id_list_len;i++) {
 			msgb_put_u16(msg, cil->id_list_lac[i]);
 		}