regulator: mcp16502: Drop useless header

The mcp16502 regulator driver includes the legacy header
<linux/gpio.h> for no reason, it is already using the proper
<linux/gpio/consumer.h> include. Drop the include.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230808-descriptors-regulator-v1-7-939b5e84dd18@linaro.org


Signed-off-by: Mark Brown <broonie@kernel.org>