Use global PCU's talloc context for all talloc calls

This allows to track memory leaks of all memory that is allocated by
talloc. Especially bitvector allocations is tracked now.
diff --git a/src/sysmo_l1_if.c b/src/sysmo_l1_if.c
index 7cb1d17..68881bf 100644
--- a/src/sysmo_l1_if.c
+++ b/src/sysmo_l1_if.c
@@ -14,6 +14,8 @@
 #include <gprs_debug.h>
 #include <pcu_l1_if.h>
 
+extern void *tall_pcu_ctx;
+
 uint32_t l1if_ts_to_hLayer2(uint8_t trx, uint8_t ts)
 {
 	return (ts << 16) | (trx << 24);
@@ -320,7 +322,7 @@
 	struct femtol1_hdl *fl1h;
 	int rc;
 
-	fl1h = talloc_zero(priv, struct femtol1_hdl);
+	fl1h = talloc_zero(tall_pcu_ctx, struct femtol1_hdl);
 	if (!fl1h)
 		return NULL;