The newly added raw_diag.c fails to build in some configurations
unless we include this header:

In file included from net/ipv4/raw_diag.c:6:0:
include/net/raw.h:71:21: error: field 'inet' has incomplete type
net/ipv4/raw_diag.c: In function 'raw_diag_dump':
net/ipv4/raw_diag.c:166:29: error: implicit declaration of function 'inet_sk'

Fixes: 432490f9 ("net: ip, diag -- Add diag interface for raw sockets")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>