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/trau_frame.c b/openbsc/src/trau_frame.c
index aa03957..2bc61a5 100644
--- a/openbsc/src/trau_frame.c
+++ b/openbsc/src/trau_frame.c
@@ -107,11 +107,13 @@
 	case TRAU_FT_DATA_DOWN:
 	case TRAU_FT_D145_SYNC:
 	case TRAU_FT_EDATA:
-		DEBUGP(DMUX, "can't decode unimplemented TRAU Frame Type 0x%02x\n", cbits5);
+		LOGP(DMUX, LOGL_NOTICE, "can't decode unimplemented TRAU "
+			"Frame Type 0x%02x\n", cbits5);
 		return -1;
 		break;
 	default:
-		DEBUGP(DMUX, "can't decode unknown TRAU Frame Type 0x%02x\n", cbits5);
+		LOGP(DMUX, LOGL_NOTICE, "can't decode unknown TRAU "
+			"Frame Type 0x%02x\n", cbits5);
 		return -1;
 		break;
 	}
@@ -162,11 +164,13 @@
 	case TRAU_FT_DATA_UP:
 	case TRAU_FT_D145_SYNC:
 	case TRAU_FT_EDATA:
-		DEBUGP(DMUX, "unimplemented TRAU Frame Type 0x%02x\n", cbits5);
+		LOGP(DMUX, LOGL_NOTICE, "unimplemented TRAU Frame Type "
+			"0x%02x\n", cbits5);
 		return -1;
 		break;
 	default:
-		DEBUGP(DMUX, "unknown TRAU Frame Type 0x%02x\n", cbits5);
+		LOGP(DMUX, LOGL_NOTICE, "unknown TRAU Frame Type "
+			"0x%02x\n", cbits5);
 		return -1;
 		break;
 	}
@@ -224,11 +228,13 @@
 	case TRAU_FT_DATA_DOWN:
 	case TRAU_FT_D145_SYNC:
 	case TRAU_FT_EDATA:
-		DEBUGP(DMUX, "unimplemented TRAU Frame Type 0x%02x\n", cbits5);
+		LOGP(DMUX, LOGL_NOTICE, "unimplemented TRAU Frame Type "
+			"0x%02x\n", cbits5);
 		return -1;
 		break;
 	default:
-		DEBUGP(DMUX, "unknown TRAU Frame Type 0x%02x\n", cbits5);
+		LOGP(DMUX, LOGL_NOTICE, "unknown TRAU Frame Type "
+			"0x%02x\n", cbits5);
 		return -1;
 		break;
 	}