ARM: s3c64xx: Add support for DMA using generic amba-pl08x driver

This patch adds all required platform-specific data and initialization
code to support the generic amba-pl08x driver on S3C64xx SoCs.

Also some compatibility definitions are added to make the transition
from legacy API to DMA engine easier. The biggest hack here is passing
const char * pointers through DMA resource, casted to unsigned long,
but this is how Samsung DMA wrappers (used to support both s3c-dma and
DMA engine in drivers) are designed.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>