dmaengine: mcf-edma: avoid warning for wrong pointer cast

This patch fixes the following compilation warning
reported during x86_64 allmodconfig build:

  drivers/dma/mcf-edma.c: In function 'mcf_edma_filter_fn':
  drivers/dma/mcf-edma.c:296:33: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
        return (mcf_chan->slave_id == (u32)param);

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Angelo Dureghello <angelo@sysam.it>
Signed-off-by: Vinod Koul <vkoul@kernel.org>