soc: mediatek: pwrap: use group of bits for pwrap capability

Use group of bits for pwrap capability instead of
elements of structure.
This patch is preparing for adding mt8183 pwrap support.

Signed-off-by: Hsin-Hsiung Wang <hsin-hsiung.wang@mediatek.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>