ASoC: rsnd: add nolock_start/stop callback

Current Renesas Sound driver requests DMA channel when .probe timing,
and release it when .remove timing. And use DMA on .start/.stop
But, Audio DMAC power ON was handled when request timing (= .probe),
and power OFF was when release timing (= .remove).
This means Audio DMAC power is always ON during driver was enabled.
To fixup this issue, it should request/release DMA channel on each
playback/recorde timing.
But, DMA channel request/release function uses mutex lock inside.
This means it will breaks current spinlock's interrupt protect.
To solve this issue, DMA channel request/release function needs to
be called from non-spinlock area. This patch adds its callback.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>