soc: mediatek: pwrap: add pwrap driver for MT6873/8192 SoCs

MT6873/8192 are highly integrated SoCs and use PMIC_MT6359 for
power management. This patch adds pwrap master driver to
access PMIC_MT6359.

Signed-off-by: Hsin-Hsiung Wang <hsin-hsiung.wang@mediatek.com>
Link: https://lore.kernel.org/r/1615563286-22126-5-git-send-email-hsin-hsiung.wang@mediatek.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>