ns2: Unify logging context via log macros

Let's avoid open-coding the printing of log context and rather rely on
log macros to prefix each log line with the relevant context.  This
helps log readability, log post processing whether by grep or more
sophisticated tools.

Change-Id: I946c0e77686d91efc5afb62031e1ac1033a9a586
diff --git a/src/gb/gprs_ns2_vc_fsm.c b/src/gb/gprs_ns2_vc_fsm.c
index 5de86f5..fc2a86a 100644
--- a/src/gb/gprs_ns2_vc_fsm.c
+++ b/src/gb/gprs_ns2_vc_fsm.c
@@ -793,8 +793,8 @@
 		osmo_fsm_inst_dispatch(fi, GPRS_NS2_EV_RX_UNITDATA, msg);
 		return 0;
 	default:
-		LOGP(DLNS, LOGL_ERROR, "NSEI=%u Rx unknown NS PDU type %s\n", nsvc->nse->nsei,
-			get_value_string(gprs_ns_pdu_strings, nsh->pdu_type));
+		LOGPFSML(fi, LOGL_ERROR, "NSEI=%u Rx unknown NS PDU type %s\n", nsvc->nse->nsei,
+			 get_value_string(gprs_ns_pdu_strings, nsh->pdu_type));
 		return -EINVAL;
 	}