iio: magnetometer: ak8974: make use of regmap_set_bits()

iio: magnetometer: ak8974: make use of regmap_set_bits()

Instead of using regmap_update_bits() and passing the mask twice, use
regmap_set_bits().

Suggested-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/20240617-review-v3-33-88d1338c4cca@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>