use new osmo_mobile_identity api (avoid deprecation)

Note: subsequent patch Iad845acb0096b75dc453105c9c16b2252879b4ca will change to
passing a struct osmo_mobile_identity in the Paging code path, instead of
passing the encoded IE data.

Change-Id: Ibb03b8e601160427944f434761ca59811d1fc12f
diff --git a/src/bts.cpp b/src/bts.cpp
index 22b4c08..c415dd4 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -369,9 +369,13 @@
 		NULL
 	};
 
-
-	LOGP(DRLCMAC, LOGL_INFO, "Add RR paging: chan-needed=%d MI=%s\n",
-		chan_needed, osmo_mi_name(mi, mi_len));
+	if (log_check_level(DRLCMAC, LOGL_INFO)) {
+		struct osmo_mobile_identity omi = {};
+		char str[64];
+		osmo_mobile_identity_decode(&omi, mi, mi_len, true);
+		osmo_mobile_identity_to_str_buf(str, sizeof(str), &omi);
+		LOGP(DRLCMAC, LOGL_INFO, "Add RR paging: chan-needed=%d MI=%s\n", chan_needed, str);
+	}
 
 	/* collect slots to page
 	 * Mark slots for every TBF, but only mark one of it.