ARM: OMAP2/3: sDMA: Correct omap_request_dma_chain(), v2

ARM: OMAP2/3: sDMA: Correct omap_request_dma_chain(), v2

Original OMAP DMA chaining design had chain_id as one of the callback
parameters. Patch 538528de0cb256f65716ab2e9613d9e920f97fe2 changed it
to use logical channel instead.

Correct the naming for callback to also use logical channel number
instead of the chain_id.

More details are on this email thread:

http://marc.info/?l=linux-omap&m=122961071931459&w=2

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>