Add mt8195 smi supporting in the bindings.

In mt8195, there are two smi-common HW, one is for vdo(video output),
the other is for vpp(video processing pipe). They connect with different
smi-larbs, then some setting(bus_sel) is different. Differentiate them
with the compatible string.

Something like this:

    IOMMU(VDO)          IOMMU(VPP)
       |                   |
 SMI_COMMON_VDO      SMI_COMMON_VPP
 ----------------     ----------------
  |      |   ...      |      |     ...
larb0 larb2  ...    larb1 larb3    ...
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210914113703.31466-2-yong.wu@mediatek.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>