ASoC: sigmadsp: Drop support support SIGMA_ACTION_DELAY

The official firmware generation tool never emitted any SIGMA_ACTION_DELAY
instructions. Keeping support for it with the new restructured loader that
also supports v2 will be difficult, so drop support for it.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>