dma: pl330: silence a compile warning

On 64 bit systems GCC warns that:

drivers/dma/pl330.c: In function ‘pl330_filter’:
drivers/dma/pl330.c:2317:21: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]

It's harmless and I have casted it away.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>