dt-bindings:iio:pressure:murata,zpa2326 yaml conversion

Simple conversion with a few minor tweaks:
* I added 1MHz max for spi-max-frequency
* I have give myself as the maintainer.  This driver was written by
  Gregor Boirie but I don't have an up to date email address for Gregor.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201031134110.724233-7-jic23@kernel.org