dmaengine: hsu: using for_each_set_bit to simplify the code

It's more cleanly to use for_each_set_bit() instead of opencoding it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220713172235.22611-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>