tipc: cleanup core.c and core.h files

Only the works of initializing and shutting down tipc module are done
in core.h and core.c files, so all stuffs which are not closely
associated with the two tasks should be moved to appropriate places.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Tested-by: Tero Aho <Tero.Aho@coriant.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/link.h b/net/tipc/link.h
index 15ca850..e96c318 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -41,6 +41,10 @@
 #include "msg.h"
 #include "node.h"
 
+/* TIPC-specific error codes
+*/
+#define ELINKCONG EAGAIN	/* link congestion <=> resource unavailable */
+
 /* Out-of-range value for link sequence numbers
  */
 #define INVALID_LINK_SEQ 0x10000