Updated asuswrt.markdown for new update (home-assistant#11426)

This describes the use of the two new configuration parameters: `interface` and `dnsmasq` and how this improves use with rt-n56u project

source/_integrations/asuswrt.markdown

@@ -67,6 +67,16 @@ require_ip:
   required: false
   type: boolean
   default: true
+interface:
+  description: "The interface of the router that you want statistics from (e.g. eth0,eth1 etc)"
+  required: false
+  type: string
+  default: eth0
+dnsmasq:
+  description: "The location of the dnsmasq.leases files"
+  required: false
+  type: string
+  default: /var/lib/misc 
 sensors:
   description: List of enabled sensors
   required: false
@@ -115,32 +125,5 @@ The example above, creates the following sensors:
 
 ## Padavan custom firmware (The rt-n56u project)
 
-The [rt-n56u project](https://bitbucket.org/padavan/rt-n56u) does not store `dnsmasq.leases` which is used to track devices at `/var/lib/misc/` as `asuswrt` do. However this integration can still be used for the rt-n56u project by linking `dnsmasq.leases` during the boot process of the router.
-
-Follow these steps to setup the link.
-
-1. SSH or Telnet into the router. (default ssh [email protected])
-2. Run the following command to find the file:
-
-```bash
-$ find / -name "dnsmasq.leases"
-```
-3. Copy or remember the full path of, example: `/tmp/dnsmasq.leases`
-4. Create the folder if it does not exist:
-
-```bash
-$ mkdir -p /var/lib/misc
-```
-5. Add the linking process to the routers started script (one line):
-
-```bash
-$ echo "/bin/ln -s /tmp/dnsmasq.leases /var/lib/misc/dnsmasq.leases" >> /etc/storage/started_script.sh
-```
-
-6. Reboot the router or link the file:
-
-```bash
-$ /bin/ln -s /tmp/dnsmasq.leases /var/lib/misc/dnsmasq.leases
-```
-
-The started script is also accessible and editable in the Router's web interface. `Advanced Settings -> Customization -> Scripts -> Custom User Script -> Run After Router Started`
+The [rt-n56u project](https://bitbucket.org/padavan/rt-n56u) does not store `dnsmasq.leases` which is used to track devices at `/var/lib/misc/` as `asuswrt` do. However this integration can still be used for the rt-n56u project by changing the dnsmasq location using the `dnsmasq` variable to `dnsmasq: '/tmp'`
+Also, to get the statistics for the `WAN` port, specify `interface: 'eth3'` as this is the interface used in the rt-n56u project