linux-phytec-ti

gpio: mcp23s08: delete req/rel_resource callbacks

When using the GPIOLIB_IRQCHIP the gpiolib provides a
straight-forward implementation of request/release resources,
rely on that instead.

Cc: Phil Reid <preid@electromag.com.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>