staging: wfx: follow compatible = vendor,chip format

As for SPI, follow "vendor,chip" format 'compatible' string also for
SDIO bus.

Fixes: 0096214a ("staging: wfx: add support for I/O access")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/96b95d52d0b613065fe655f1d0fe9d7c6adf65fb.1581416843.git.mirq-linux@rere.qmqm.pl


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>