[RAW]: Add raw_hashinfo member on struct proto.

Sorry for the patch sequence confusion :| but I found that the similar
thing can be done for raw sockets easily too late.

Expand the proto.h union with the raw_hashinfo member and use it in
raw_prot and rawv6_prot. This allows to drop the protocol specific
versions of hash and unhash callbacks.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>