Remove some checks to make VLAN's work

[fma965]

This can be a good start to get multiple subnets/ip ranges working.

It does technically allow people to put invalid IP's in but i think perhaps a checkbox could be added or something?

This is used by myself in conjunction with https://github.com/Fma965/ASUS-DSL-AC68U-VLAN for VLAN support on the DSL-AC68U

I'm not really expecting you to merge this as is, but it's here if you wanted it,i'll keep my non Scarf interfaced version on https://github.com/Fma965/YazDHCP anyway