Add counters: pcu.bts.N.pch.requests.timeout

Implement T3113 for paging over PCH with default value of 7s (same as
T3113 in OsmoBSC). Increase the new counter on timeout.

Related: SYS#4878
Change-Id: I97475c3dbe2cf00b9cbfec39e93a3c65cb7f749f
diff --git a/src/gprs_rlcmac.cpp b/src/gprs_rlcmac.cpp
index ffa656c..22b12df 100644
--- a/src/gprs_rlcmac.cpp
+++ b/src/gprs_rlcmac.cpp
@@ -26,6 +26,7 @@
 #include <pcu_l1_if.h>
 #include <gprs_rlcmac.h>
 #include <bts.h>
+#include <bts_pch_timer.h>
 #include <encoding.h>
 #include <tbf.h>
 #include <gprs_debug.h>
@@ -48,6 +49,7 @@
 		return -1;
 	}
 	bts_do_rate_ctr_inc(bts, CTR_PCH_REQUESTS);
+	bts_pch_timer_start(bts, mi->imsi);
 	pcu_l1if_tx_pch(bts, paging_request, plen, pgroup);
 	bitvec_free(paging_request);