Fix counting received IPA packets in server mode

When operating an IPA ASP in server mode, we were not counting the
packets using the related stat item:

For example:

OsmoSTP# show stats
Ungrouped counters:
SIGTRAN Application Server Process (6)('asp-dyn-5'):
 Total number of packets received:        0 (0/s 0/m 0/h 0/d)
 Total number of packets transmitted: 235370503 (129/s 7682/m 442447/h 11342653/d)

This patch adds the missing counter increment.

back-port of Change-Id I75881d115b5c2c2567c4731bcf2cabe11f367117 from master
Closes: SYS#6600

Change-Id: I96488e4ea10e00f5f03387e33dc58e4b5016458f
---
M src/osmo_ss7_asp.c
1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/osmo_ss7_asp.c b/src/osmo_ss7_asp.c
index 596e7ae..e1c197c 100644
--- a/src/osmo_ss7_asp.c
+++ b/src/osmo_ss7_asp.c
@@ -905,7 +905,7 @@
 		return -1;
 	}
 	msg->dst = asp;
-
+	rate_ctr_inc2(asp->ctrg, SS7_ASP_CTR_PKT_RX_TOTAL);
 	return ipa_rx_msg(asp, msg, ofd->fd & 0xf);
 }
 

