dmaengine: coh901318: fix pointer cast warnings

On some systems, pointer can be large than unsigned int, triggering warning
pointer-to-int-cast on conversion.

drivers/dma/coh901318.c: In function 'coh901318_filter_id':
drivers/dma/coh901318.c:1769:23: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  unsigned int ch_nr = (unsigned int) chan_id;

Also, converting an iomem pointer for print leads to warn on some system
which can be avoided with %p specfier

drivers/dma/coh901318.c: In function 'coh901318_probe':
drivers/dma/coh901318.c:2748:3: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
   (u32) base->virtbase);

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>