DMA: PL330: Merge PL330 driver into drivers/dma/

Currently there were two part of DMAC PL330 driver for
support old styled s3c-pl330 which has been merged into
drivers/dma/pl330.c driver. Actually, there is no reason
to separate them now.

Basically this patch merges arch/arm/common/pl330.c into
drivers/dma/pl330.c driver and removes useless exported
symbol, externed function and so on.

The newer pl330 driver tested on SMDKV310 and SMDK4212 boards

Cc: Jassi Brar <jassisinghbrar@gmail.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Boojin Kim <boojin.kim@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>