Add COH 901 318 DMA block driver v5

This patch adds support for the ST-Ericsson COH 901 318 DMA block,
found in the U300 series platforms. It registers a DMA slave for
device I/O and also a memcpy slave for memcpy.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>