pcu_sock: add basic pcu interface support

Adds a basic version of a pcu socket interface, similar
to the one that can be found in osmo-bts.

Change-Id: Ib13cb4099d12fa71e9e0b8727e19ab29e11909b2
diff --git a/openbsc/src/libcommon/debug.c b/openbsc/src/libcommon/debug.c
index 0f82211..f29f168 100644
--- a/openbsc/src/libcommon/debug.c
+++ b/openbsc/src/libcommon/debug.c
@@ -175,6 +175,11 @@
 		.description = "SCCP User Adaptation Protocol",
 		.enabled = 1, .loglevel = LOGL_DEBUG,
 	},
+	[DPCU] = {
+		.name = "DPCU",
+		.description = "PCU Interface",
+		.enabled = 1, .loglevel = LOGL_DEBUG,
+	},
 };
 
 static int filter_fn(const struct log_context *ctx, struct log_target *tar)