DMA: PL330: Add check if device tree compatible

This patch register the dma controller with generic dma helpers only
in DT case. This also adds some extra error handling in the driver.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Reported-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>