riscv: dts: spacemit: k3: add clock tree

riscv: dts: spacemit: k3: add clock tree

Add clock support to SpacemiT K3 SoC, the clock tree consist of several
blocks which are APBC, APMU, DCIU, MPUM.

Link: https://lore.kernel.org/r/20260304-01-dts-uart-full-v1-1-50a0aa53a245@kernel.org
Signed-off-by: Yixun Lan <dlan@kernel.org>