ASoC: cs35l41: Use regmap_read_poll_timeout to wait for OTP boot

Just clean up the code a little by using the helper rather than open
coding waiting for OTP_BOOT_DONE.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210914141349.30218-2-ckeepax@opensource.cirrus.com


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