neigh: convert parms to an array

neigh: convert parms to an array

This patch converts the neigh param members to an array. This allows easier
manipulation which will be needed later on to provide better management of
default values.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>