ASoC: tlv320adcx140: Idle the device while writing registers

It was observed that if the device was active and register writes were
performed there were some unwanted behaviors particularly when writing
the word length and some filter options. So when writing to the device
the device should be placed in sleep mode and then exit sleep mode once
the register update is complete.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20200915190606.1744-1-dmurphy@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>