[DCCP]: Move dccp_[un]hash from ipv4.c to the core

As this is used by both ipv4 and ipv6 and is not ipv4 specific.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc net/dccp/dccp.h
Simple merge

diff --cc net/dccp/ipv4.c
Simple merge

diff --cc net/dccp/ipv6.c
Simple merge

diff --cc net/dccp/proto.c
Simple merge