sound: ASoC: Blackfin: SPORT peripheral interface driver

SPORT is a serial port which can support serveral serial communication
protocols.  It can be used as I2C/PCM/AC97. For further information,
please look up the HRM.

[Additional coding standards fixes by Mark Brown.]

Signed-off-by: Cliff Cai <cliff.cai@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>