ASoC: nau8825: fix issue that pop noise when start capture

In skylake platform, we hear a loud pop noise(0 dB) at start of
audio capture power up sequence. This patch removes the pop noise
from the recording by adding a delay before enabling ADC.

Signed-off-by: Abhijeet Kumar <abhijeet.kumar@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>