ASoC: kirkwood-i2s: more pause-mode fixes

Don't even momentarily set the pause status when starting the channel;
if we do, we should check the busy bit to ensure that we comply with
the spec.  In any case, it isn't necessary; we will not active on a
START event so there is no need to pause the DMA.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>