ASoC: DaVinci: pcm, rename variables in prep for ping/pong

Rename variable master_lch to asp_channel
Rename variable slave_lch to asp_link[0]
Rename local variables:
	lch to link
	count to asp_count
	src to asp_src
	dst to asp_dst

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>