warnings from recent format patch

[Stephen Hemminger <shemminger@vyatta.com>]

Even if you can't run it, please compile and run sparse on your
code.

 CC [M]  net/sunrpc/xprtsock.o
net/sunrpc/xprtsock.c: In function ‘xs_format_ipv4_peer_addresses’:
net/sunrpc/xprtsock.c:287: warning: too many arguments for format

static void xs_format_ipv4_peer_addresses(struct rpc_xprt *xprt,
					  const char *protocol,
					  const char *netid)
{
	struct sockaddr_in *addr = xs_addr_in(xprt);
	char *buf;

	buf = kzalloc(20, GFP_KERNEL);
	if (buf) {
		snprintf(buf, 20, "pI4", &addr->sin_addr.s_addr);
                                   ^
                                   missing %