ASoC: rt5514-spi: check irq status to schedule data copy

For wake on voice use case, we need to copy data from DSP buffer
to PCM stream when system wakes up by voice. However the edge
triggered IRQ could be missed when system wakes up, in that case
the irq function will not be called. Fix that by checking the irq
status bit and schedule data copy accordingly.

Signed-off-by: Hsin-Yu Chao <hychao@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>