ASoC: DAPM: Add APIs to create individual DAPM controls.

The topology core needs to be able to create individual widget controls at
runtime and driver init. Add a regular locked and unlocked API calls to
facilitate this requirement.

The unlocked call is used by the topology core during component driver
probing where the card dapm_mutex is held by the ASoC core and the locked
version at non component driver probe time.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>