arm: allwinner: Set aw_ccu to BUS_PASS_BUS
In r350842 I've switched the bus pass to resource so it matches the other
clock drivers but this cannot work as this drivers is meant to match
the dts node '/clocks' and if we don't do it at this pass simplebus is
catching this node and we cannot attach.
This solve booting on Allwinner boards that are still using /clocks (A20 SoC)
MFC after: 3 days