gpio: mcp23s08: Select REGMAP/REGMAP_I2C to fix build error

[ Upstream commit e8e1a5b5679b1ae1ff03a3883b011b84e7226171 ]

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

Fixes: ("3d84fdb3f0b5 gpio: mcp23s08: use regmap")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>