ASoC: sirf: Add SiRF audio port driver is used by SiRF internal audio codec

This driver is used by SIRF internal audio codec.
Use dedicated SiRF audio port TXFIFO and RXFIFO
Supports two DMA channels for SiRF audio port TXFIFO and RXFIFO
The audio port like as audio bus such as i2s.

Signed-off-by: Rongjun Ying <rongjun.ying@csr.com>
Signed-off-by: Mark Brown <broonie@linaro.org>