dmaengine: sun6i: support parameterized compatible strings

This patch adds support for hardware parameters tied to compatible
strings, so similar hardware can reuse the driver.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>