pcu_l1_if: constify the argument of pcu_rx_info_ind()

Change-Id: I0b146c9f8c1e566c3aff4bd7869ca9699f888d4f
diff --git a/src/pcu_l1_if.cpp b/src/pcu_l1_if.cpp
index 99d0927..7d0345e 100644
--- a/src/pcu_l1_if.cpp
+++ b/src/pcu_l1_if.cpp
@@ -485,7 +485,7 @@
 	return rc;
 }
 
-static int pcu_rx_info_ind(struct gsm_pcu_if_info_ind *info_ind)
+static int pcu_rx_info_ind(const struct gsm_pcu_if_info_ind *info_ind)
 {
 	struct gprs_rlcmac_bts *bts = bts_main_data();
 	struct gprs_bssgp_pcu *pcu;