gprs/gprs_llc: count UI frames over SAPI in the statistics

Change-Id: I5f38d70e046ce9ca1342e6f862329dc3cded8995

openbsc/src/gprs/gprs_llc.c

@@ -774,6 +774,9 @@ int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command,
 		}
 	}
 
+	rate_ctr_inc(&sgsn->rate_ctrs->ctr[CTR_LLC_DL_PACKETS]);
+	rate_ctr_add(&sgsn->rate_ctrs->ctr[CTR_LLC_DL_BYTES], msg->len);
+
 	/* Identifiers passed down: (BVCI, NSEI) */
 
 	/* Send BSSGP-DL-UNITDATA.req */