pinctrl: mcp23s08: Propagate error code from device_property_read_u32()

Return error code from device_property_read_u32() as is in mcp23s08_probe().
While here, drop status variable in mcp23s08_irq_set_type() which always 0.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200407173849.43628-6-andriy.shevchenko@linux.intel.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>