arm64: dts: renesas: Extract common ULCB board support

The Renesas ULCB development board can be equipped with either an R-Car
H3 or M3-W SiP, which are pin-compatible.  Both boards use different
DTBs.

Reduce duplication by extracting common ULCB board support into its own
.dtsi file.  References to SoC-specific clocks are handled through cpp
definitions.  Sort device nodes while at it.

For H3ULCB, there are no functional changes.

For M3ULCB, the following new devices are now described in DT:
  - External audio, CAN, and PCIe clocks,
  - CS2000 clock generator,
  - AK4613 Audio Codec.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>