gpio: mcp23s08: Add option to configure IRQ output polarity as active high

Default is active low, but if property is specified in DT set INTPOL flag.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2 files changed