net: guard tcp_set_keepalive() to tcp sockets

Its possible to use RAW sockets to get a crash in
tcp_set_keepalive() / sk_reset_timer()

Fix is to make sure socket is a SOCK_STREAM one.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
void sock_update_netprioidx(struct sock *sk, struct task_struct *task)
{
	if (in_interrupt())
		return;

	sk->sk_cgrp_prioidx = task_netprioidx(task);
}

void sock_update_netprioidx(struct sock *sk, struct task_struct *task)
{
	if (in_interrupt())
		return;

	sk->sk_cgrp_prioidx = task_netprioidx(task);
}
