lib: refactory cisco access list net wildcard

lib: refactory cisco access list net wildcard

Wildcards bits have the opposite representation of a network mask,
example:

192.168.0.0/24 has the following netmask 255.255.0.0 and the wildcard
representation is 0.0.255.255.

To avoid future confusion lets put those definitions into a macro so we
know for sure which form to use.

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>