dmaengine: nbpfaxi: Use of_device_get_match_data() helper

Use the of_device_get_match_data() helper instead of open coding.
Note that when used with DT, there's always a valid match.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>