bts: delete pch_timer list in destructor

Run bts_pch_timer_remove() on each entry of the BTS specific pch_timer
list, so we don't have a memory leak and so the timer doesn't
potentially fire for a deallocated BTS.

Fixes: d3c7591 ("Add counters: pcu.bts.N.pch.requests.timeout")
Change-Id: Ia5e33d1894408e93a51c452002ef2f5758808269
diff --git a/src/bts_pch_timer.c b/src/bts_pch_timer.c
index 386a583..20373ac 100644
--- a/src/bts_pch_timer.c
+++ b/src/bts_pch_timer.c
@@ -83,3 +83,12 @@
 	if (p)
 		bts_pch_timer_remove(p);
 }
+
+void bts_pch_timer_stop_all(struct gprs_rlcmac_bts *bts)
+{
+	struct bts_pch_timer *p, *n;
+
+	llist_for_each_entry_safe(p, n, &bts->pch_timer, entry) {
+		bts_pch_timer_remove(p);
+	}
+}