Adding support for RG-R6

It has the same chipset as Linksys E8450 (aka Belkin RT3200), MediaTek MT7622BV, and the switch is also the same, MediaTek MT7531BE.
https://fcc.report/FCC-ID/2AX5J-R6/5491616.pdf.

It should be easy to support.

https://www.amazon.com/Reyee-2-Pack-Replaces-Wireless-Extenders/dp/B0BY2KF88C?th=1

You need to get the device on hand and starting to console in to make "easy to support" to happen.

okay I will try to get this one.