regulator: fan53555: Explicitly include bits header

regulator: fan53555: Explicitly include bits header

Since commit f2a9eb975ab2 ("regulator: fan53555: Add support for
FAN53526") the driver makes use of the BIT() macro, but relies on the
bits header being implicitly included.

Explicitly pull the header in to avoid potential build failures in some
configurations.

While here, reorder include directives alphabetically.

Fixes: f2a9eb975ab2 ("regulator: fan53555: Add support for FAN53526")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Link: https://lore.kernel.org/r/20230406171806.948290-3-cristian.ciocaltea@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>