gsm411_send_rp_data(): add FIXME for MSC_CTR_SMS_DELIVERED

Change-Id: I5380035294d2fca481620638b59eae779670e9f8
diff --git a/src/libmsc/gsm_04_11.c b/src/libmsc/gsm_04_11.c
index cbacb43..ed36302 100644
--- a/src/libmsc/gsm_04_11.c
+++ b/src/libmsc/gsm_04_11.c
@@ -1280,6 +1280,7 @@
 	/* Encode RP-UD itself (SM TPDU) */
 	msgb_lv_put(msg, sm_rp_ud_len, sm_rp_ud);
 
+	/* FIXME: MT SMS is not guaranteed to be delivered (e.g. the MS may be detached) */
 	rate_ctr_inc(rate_ctr_group_get_ctr(net->msc_ctrs, MSC_CTR_SMS_DELIVERED));
 
 	return gsm411_rp_sendmsg(&trans->sms.smr_inst, msg,