dmaengine: edma: fixed wrongly initialized data parameter to the edma callback

The "data" parameter passed indirectly to the edma_callback() should be
edma_chan and not the dma_chan.

This bug was so far harmless since the offset of struct dma_chan within struct
edma_chan is 0. However as soon as someone changes struct edma_chan this would
cause troubles.

Signed-off-by: Petr Kulhavy <petr@barix.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>