IuPS: add Iu response to delete_pdp_conf()

Change-Id: I6d601586101c0a004b2243633fab48db82b44b7c
diff --git a/openbsc/src/gprs/sgsn_libgtp.c b/openbsc/src/gprs/sgsn_libgtp.c
index 45eff63..35d5dab 100644
--- a/openbsc/src/gprs/sgsn_libgtp.c
+++ b/openbsc/src/gprs/sgsn_libgtp.c
@@ -485,6 +485,13 @@
 		if (pctx->mm->ran_type == MM_CTX_T_GERAN_Gb) {
 			/* Deactivate the SNDCP layer */
 			sndcp_sm_deactivate_ind(&pctx->mm->gb.llme->lle[pctx->sapi], pctx->nsapi);
+		} else {
+#ifdef BUILD_IU
+			/* Deactivate radio bearer */
+			iu_rab_deact(pctx->mm->iu.ue_ctx, 1);
+#else
+			return -ENOTSUP;
+#endif
 		}
 
 		/* Confirm deactivation of PDP context to MS */