dmaengine: ioatdma: move all the init routines

Moving all the init routines to init.c and fixup anything broken during
the move.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>