dmaengine: s3c24xx: fix pointer cast warnings

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

drivers/dma/s3c24xx-dma.c: In function 's3c24xx_dma_filter':
drivers/dma/s3c24xx-dma.c:1421:24: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]

Use a long value for type conversion.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>