ASoC: topology: Remove unused functions from topology API

ASoC: topology: Remove unused functions from topology API

Topology API exposes snd_soc_tplg_widget_remove and
snd_soc_tplg_widget_remove_all, but both are nowhere used. All current
users load and unload topology as a whole. As following commits
introduce resource managed memory, remove them to simplify code and
reduce maintenance burden.

Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20201030145427.3497990-2-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>