ASoC: rt1015: increase the time to detect BCLK

To meet the most platform, the detection time should be increased to
avoid that the flushing DAC data fails.

Signed-off-by: Shuming Fan <shumingf@realtek.com>
Link: https://lore.kernel.org/r/20201113092125.19206-1-shumingf@realtek.com


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