IuPS: explicitly check RAN type; move comment

Change-Id: I054d72590dfb2012f6f8506d3a5f8fd2953194e1
diff --git a/src/gprs/gprs_gmm.c b/src/gprs/gprs_gmm.c
index 83b1a70..577af1b 100644
--- a/src/gprs/gprs_gmm.c
+++ b/src/gprs/gprs_gmm.c
@@ -971,10 +971,12 @@
 static int gsm48_tx_gmm_ra_upd_ack(struct sgsn_mm_ctx *mm);
 
 #ifdef BUILD_IU
+/* Send RAB activation requests for all PDP contexts */
 void activate_pdp_rabs(struct sgsn_mm_ctx *ctx)
 {
-	/* Send RAB activation requests for all PDP contexts */
 	struct sgsn_pdp_ctx *pdp;
+	if (ctx->ran_type != MM_CTX_T_UTRAN_Iu)
+		return;
 	llist_for_each_entry(pdp, &ctx->pdp_list, list) {
 		iu_rab_act_ps(pdp->nsapi, pdp, 1);
 	}