ASoC: davinci-mcasp: Configure the AFIFO and DMA burst size at the same place

Move the dma_params->fifo_level and dma_data->maxburst configuration to the
mcasp_common_hw_param() function where we configure the AFIFO registers.
It makes the code regarding to AFIFO and DMA configuration more easy to
follow since it is now clear how the AFIFO and how the DMA is going to be
configured.
Previously this has been done in two functions using a bit different
calculation form - which ended up with the same result in both case at the
end, but it was confusing.

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