dmaengine: dw: Simplify DT property parser

Since we converted internal data types to match DT, there is no need to have
an intermediate conversion layer, hence drop a few conditionals and for loops
for good.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20210802184355.49879-3-andriy.shevchenko@linux.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>