soundwire: cadence: use FIELD_{GET|PREP}

use FIELD_{GET|PREP} in cadence driver to get/set field values instead
of open coding masks and shift operations.

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Tested-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200903114504.1202143-7-vkoul@kernel.org


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