tipc: merge port message reception into socket reception function

In order to reduce complexity and save a call level during message
reception at port/socket level, we remove the function tipc_port_rcv()
and merge its functionality into tipc_sk_rcv().

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc net/tipc/link.c
Simple merge

diff --cc net/tipc/net.c
Simple merge

diff --cc net/tipc/port.c
Simple merge

diff --cc net/tipc/port.h
Simple merge

diff --cc net/tipc/socket.c
Simple merge

diff --cc net/tipc/socket.h
Simple merge