ARM: OMAP: Pass logical DMA channel number always to callback handlers

This makes parameter passing to DMA handlers uniform between non-chained
and chained transfers and makes debugging easier. Additional data like
chain_id can be always passed to handlers via callback data if needed.

Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>