This driver now using devm_regmap_init/devm_regmap_init_i2c, so it needs
to select REGMAP/REGMAP_I2C accordingly.

Fixes: ("3d84fdb3 gpio: mcp23s08: use regmap")
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Acked-By: NSebastian Reichel <sre@kernel.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>