davinci: edma: use a more intuitive name for edma_info

'edma_info' structure inside the edma driver represents
a single instance of edma channel controller. Call it
'edma_cc' instead. This also avoids readers confusing
it with an instance of edma_soc_info structre which
carries the platform data for a single channel controller
instance.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>