Add SI2quater support to SI3

Advertise SI2 quater presence and location (if available) using SI3
according to 3GPP TS 44.018 ยง 10.5.2.34
diff --git a/openbsc/src/libbsc/rest_octets.c b/openbsc/src/libbsc/rest_octets.c
index 4545794..83cf2ec 100644
--- a/openbsc/src/libbsc/rest_octets.c
+++ b/openbsc/src/libbsc/rest_octets.c
@@ -129,6 +129,15 @@
 	/* GPRS Indicator */
 	append_gprs_ind(&bv, &si3->gprs_ind);
 
+	/* 3G Early Classmark Sending Restriction controlled by
+	 * early_cm_ctrl above */
+	bitvec_set_bit(&bv, H);
+
+	if (si3->si2quater_indicator) {
+		bitvec_set_bit(&bv, H); /* indicator struct present */
+		bitvec_set_uint(&bv, 0, 1); /* message is sent on BCCH Norm */
+	}
+
 	bitvec_spare_padding(&bv, (bv.data_len*8)-1);
 	return bv.data_len;
 }