dmaengine: s3c24xx-dma: use DMA_COMPLETE for dma completion status

Use the recently introduced DMA_COMPLETE instead of DMA_SUCCESS.
Without this patch we get the following build error:
drivers/dma/s3c24xx-dma.c: In function ‘s3c24xx_dma_tx_status’:
drivers/dma/s3c24xx-dma.c:798:13: error: ‘DMA_SUCCESS’ undeclared
(first use in this function)

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>