wlcore: Add support for DT platform data

When running with DT, we no longer have a board file that can set up the
platform data for wlcore. Allow this data to be passed from DT.

Since some platforms use a gpio-irq, add support for passing either the
irq number or the gpio number. For the latter case, the driver will
request the gpio and convert it to the irq number. If an irq is
specified, it'll be used as is.

Signed-off-by: Ido Yariv <ido@wizery.com>