ASoC: topology: Unify code for creating standalone and widget mixer control

Code used to create standalone and widget mixer control is same, with
exception that in standalone case dynamic object needs to be registered
and control created directly.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Link: https://patch.msgid.link/20240627101850.2191513-13-amadeuszx.slawinski@linux.intel.com


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