spi: sc18is602: Add reset control via gpio pin.

This sc18is602 has a reset pin that may need to be deasserted.
Add optional binding to specifiy the reset pin via a gpio and deassert
during probe.

Signed-off-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Mark Brown <broonie@kernel.org>
1 file changed