ASoC: pxa: pxa-ssp: set dma filter data from startup hook

With the new dmaengine implementation, the filter_data parameter has
to be set earlier, from pxa_ssp_startup().

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>