soc: mediatek: pm-domains: Add SMI block as bus protection block

Apart from the infracfg block, the SMI block is used to enable the bus
protection for some power domains. Add support for this block.

Signed-off-by: Matthias Brugger <mbrugger@suse.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20201030113622.201188-7-enric.balletbo@collabora.com


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