ASoC: rt5677: Mark reg RT5677_PWR_ANLG2 as volatile

ASoC: rt5677: Mark reg RT5677_PWR_ANLG2 as volatile

The codec dies when RT5677_PWR_ANLG2(MX-64h) is set to 0xACE1
while it's streaming audio over SPI. The DSP firmware turns
on PLL2 (MX-64 bit 8) when SPI streaming starts.  However regmap
does not believe that register can change by itself. When
BST1 (bit 15) is turned on with regmap_update_bits(), it doesn't
read the register first before write, so PLL2 power bit is
cleared by accident.

Marking MX-64h as volatile in regmap solved the issue.

Signed-off-by: Ben Zhang <benzh@chromium.org>
Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
Link: https://lore.kernel.org/r/20191106011335.223061-6-cujomalainey@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>