net: use %pF for /proc/net/ptype

Technically, patch changes format for modules, but I think nobody cares.

	-86dd          :ipv6:ipv6_rcv+0x0
	+86dd          ipv6_rcv+0x0/0x400 [ipv6]

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>