ASoC: omap-abe-twl6040: Remove support for pdata (legacy boot)

Just recently OMAP4 legacy boot support has been removed. No reason to keep
the code used by the legacy boot (pdata based) since neither OMAP4 or OMAP5
can boot in this mode.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>