Do not recommend custom DHCP option on internal VLAN

This change removes from the README the recommendation to add custom
DHCP option 60 to the internal IPTV VLAN, since it is not actually
necessary.

Author: fabianishere

README.md

@@ -98,12 +98,6 @@ additional DHCP options. You can add these DHCP options as follows:
    order to reduce interference of other devices on the network.
 3. Enable **Advanced Configuration > IGMP Snooping**, so IPTV traffic is only
    sent to devices that should receive it.
-4. Go to **DHCP > Custom DHCP Option** and add the following options:
-
-   | Name       | Code | Type       | Value               |
-   |------------|:----:|------------|---------------------|
-   | IPTV-Class |  60  | Text       | IPTV_RG             |
-
 
 ## Configuring Helper Tool