regulator: fan53555: Remove unused *_SLEW_SHIFT definitions

Commit b61ac767 ("regulator: fan53555: Convert to use
regulator_set_ramp_delay_regmap") removed the slew_shift member from
struct fan53555_device_info, hence the {CTL,TCS}_SLEW_SHIFT definitions
remained unused.  Drop them.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Link: https://lore.kernel.org/r/20230406194158.963352-5-cristian.ciocaltea@collabora.com


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