ASoC: cs42l56: Fix misuse of regmap_update_bits

Using regmap_update_bits(..., mask, 1) with 'mask' following (1 << k)
and k greater than 0 is wrong. Indeed, _regmap_update_bits will perform
(mask & 1), which results in 0 if LSB of mask is 0. Thus the call
regmap_update_bits(..., mask, 1) is in reality equivalent to
regmap_update_bits(..., mask, 0).

In such a case, the correct use is regmap_update_bits(..., mask, mask).

This driver is performing such a mistake with the CS42L56_AIN*_REF_MASK
masks, which equal 0x10, 0x20, 0x40 and 0x80. Fix the driver to make it
consistent with the API. Please note that this change is untested,
as I do not have this piece of hardware. Testers are welcome!

Signed-off-by: Florian Vaussard <florian.vaussard@heig-vd.ch>
Reviewed-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Brian Austin <brian.austin@cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>