ARM: SAMSUNG: Add common DMA operations

This patch adds common DMA operations which are used for Samsung DMA
drivers. Currently there are two types of DMA driver for Samsung SoCs.
The one is S3C-DMA for S3C SoCs and the other is PL330-DMA for S5P SoCs.
This patch provides funcion pointers for common DMA operations to DMA
client driver like SPI and Audio. It makes DMA client drivers support
multi-platform.
In addition, this common DMA operations implement the shared actions
that are needed for DMA client driver. For example shared actions are
filter() function for dma_request_channel() and parameter passing for
device_prep_slave_sg().

Signed-off-by: Boojin Kim <boojin.kim@samsung.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>