dmaengine: PL08x: Add support for PL080S variant

PL080S is a modified version of PL080 that can be found on Samsung SoCs,
such as S3C6400 and S3C6410.

It has different offset of CONFIG register, separate CONTROL1 register
that holds transfer size and larger maximum transfer size.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>