net: neighbour: Document {mcast, ucast}_solicit, mcast_resolicit.

	gratuitous arp frame, the arp table will be updated regardless

	if this setting is on or off.

mcast_solicit - INTEGER

	The maximum number of multicast probes in INCOMPLETE state,

	when the associated hardware address is unknown.  Defaults

	to 3.

ucast_solicit - INTEGER

	The maximum number of unicast probes in PROBE state, when

	the hardware address is being reconfirmed.  Defaults to 3.

app_solicit - INTEGER

	The maximum number of probes to send to the user space ARP daemon

	via netlink before dropping back to multicast probes (see

	mcast_solicit).  Defaults to 0.

	mcast_resolicit).  Defaults to 0.

mcast_resolicit - INTEGER

	The maximum number of multicast probes after unicast and

	app probes in PROBE state.  Defaults to 0.

disable_policy - BOOLEAN

	Disable IPSEC policy (SPD) for this interface