[INET]: style updates for the inet_sock->is_icsk assignment fix

A quick patch to change the inet_sock->is_icsk assignment to better fit with
existing kernel coding style.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>