Only add xradio and xradio firmware for the Orange Pi Zero, since no other device uses this chipset.
Changelog-entry: Add support for XR819 Wifi on Orange Pi Zero board
From the list of supported boards, only the Orange Pi Plus2 board has
this WiFi chipset so let's not include it for all.
Changelog-entry: Include the RTL8189ES / RTL8189ETV driver only for the Orange Pi Plus2 board
Signed-off-by: Florin Sarbu <florin@balena.io>