ASoC: rt5514: Voice wakeup support.

If the rt5514 Wake on Voice device is opened while suspended, it will
be able to wake up the system when a voice command is detected.
This patch also supports user-space policy to override wakeup behavior
by /sys/bus/spi/drivers/rt5514/spi2.0/power/wakeup.

Signed-off-by: Chinyue Chen <chinyue@chromium.org>
Signed-off-by: Oder Chiou <oder_chiou@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>