dmaengine: at_xdmac: fix to pass correct device identity to free_irq()

dmaengine: at_xdmac: fix to pass correct device identity to free_irq()

BugLink: http://bugs.launchpad.net/bugs/1631468
commit 6a8b0c6b18f62a277ffb2139d0c0253fe35d7feb upstream.

free_irq() expects the same device identity that was passed to
corresponding request_irq(), otherwise the IRQ is not freed.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>