Correct i2c DTS node names in mt8173.dtsi.

Add spi DTS node to the mt8173 and mt8173-evb.

Add dts nodes for the subsystem clocks on mt8173.
This includes mmsys, imgsys, vdecsys, vencsys, vencltsys.

Add clock nodes to the scpsys binding, which are needed to
access the registers of venc and venc_lt power domains.

* tag 'v4.3-next-arm64' of https://github.com/mbgg/linux-mediatek:
  arm64: dts: mt8173: Add clocks for SCPSYS unit
  arm64: dts: mt8173: Add subsystem clock controller device nodes
  arm64: dts: Add spi bus dts
  arm64: mt8173.dtsi: correct i2c node names
Signed-off-by: Olof Johansson <olof@lixom.net>