ASoC: mchp-spdiftx: use regmap_update_bits()

Use regmap_update_bits() instead of regmap_read(), running variable,
regmap_write(). There is no need for extra variables and checks around
it as regmap_update_bits() already does this. With this code becomes
simpler.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230301113807.24036-3-claudiu.beznea@microchip.com


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