Recommendation Readme Update

[rufreakde]

Please add the following prerequisite test before one starts trying to make build etc into the readme:

iw phy | grep 'Device supports'

Print should contain something like: Device supports active monitor

This precheck would have saved me a lot of time... since I use Raspi 4b and the wlan doesnt support active monitor...

[Frostie314159]

If you're looking for a WNIC, that works with owl, I can recommend the AWUS036AC. Works for me.