This patch adds xradio wireless driver for SDIO WiFi chip XR819.
The out-of-tree driver is sourced from fifteenhex's work
on github https://github.com/fifteenhex/xradio
Signed-off-by: Sergey Matyukevich <geomatsi@gmail.com>
[Thomas: add entry in DEVELOPERS file.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>