ASoC: dapm: Sprinkle lockdep asserts through the code

Try to spot locking issues by asserting that the DAPM mutex is held when
it should be. There's a bit of fun due to us not requiring the lock to be
held prior to the card being instantiated which mean we need to wrap the
assert in some paths and this isn't methodical by any stretch of the
imagination.

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