dt-bindings: staging: wfx: silabs,wfx yaml conversion

The device can be connected on SPI or on SDIO. The original file
described the two options separately. So, most of the file had to be
rewritten in order to match with the Yaml requirements.

Some device requirements are still written in the comments since they
cannot been expressed with the current scheme (e.g. reg must be set to 1
with SDIO, interrupt is mandatory with SPI, reset-gpio in SPI is
replaced by mmc-pwrseq in SDIO, etc...).

The examples provided have also been reworked in order to make
dt_binding_check happy.

Finally, also fix typo in the name of the file (siliabs instead of
silabs)

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20201007101943.749898-7-Jerome.Pouiller@silabs.com


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