logging: introduce log levels at caller site

This introduces a new LOGP() macro together with LOGL_* definition to
support multiple log levels (severities) throughout the codebase.

Please note that the actual logging system does not use them yet,
in this patch we simply introduce the new macros at the caller site.
diff --git a/openbsc/src/mncc.c b/openbsc/src/mncc.c
index de17657..a5efc73 100644
--- a/openbsc/src/mncc.c
+++ b/openbsc/src/mncc.c
@@ -85,8 +85,7 @@
 
 	{"GSM_TRAU_FRAME",	0x0300},
 
-	{NULL, 0}
-};
+	{NULL, 0} };
 
 static LLIST_HEAD(call_list);
 
@@ -146,8 +145,8 @@
 	
 	/* transfer mode 1 would be packet mode, which was never specified */
 	if (setup->bearer_cap.mode != 0) {
-		DEBUGP(DMNCC, "(call %x) We don't support packet mode\n",
-			call->callref);
+		LOGP(DMNCC, LOGL_NOTICE, "(call %x) We don't support "
+			"packet mode\n", call->callref);
 		mncc_set_cause(&mncc, GSM48_CAUSE_LOC_PRN_S_LU,
 				GSM48_CC_CAUSE_BEARER_CA_UNAVAIL);
 		goto out_reject;
@@ -155,8 +154,8 @@
 
 	/* we currently only do speech */
 	if (setup->bearer_cap.transfer != GSM_MNCC_BCAP_SPEECH) {
-		DEBUGP(DMNCC, "(call %x) We only support voice calls\n",
-			call->callref);
+		LOGP(DMNCC, LOGL_NOTICE, "(call %x) We only support "
+			"voice calls\n", call->callref);
 		mncc_set_cause(&mncc, GSM48_CAUSE_LOC_PRN_S_LU,
 				GSM48_CC_CAUSE_BEARER_CA_UNAVAIL);
 		goto out_reject;
@@ -406,7 +405,7 @@
 		rc = mncc_send(net, MNCC_RETRIEVE_REJ, data);
 		break;
 	default:
-		DEBUGP(DMNCC, "(call %x) Message unhandled\n", callref);
+		LOGP(DMNCC, LOGL_NOTICE, "(call %x) Message unhandled\n", callref);
 		break;
 	}