Orange Pi5 kernel

* Clock bindings for Energy Micro efm32 Giant Gecko's Clock Management Unit

Required properties:
- compatible: Should be "efm32gg,cmu"
- reg: Base address and length of the register set
- interrupts: Interrupt used by the CMU
- #clock-cells: Should be <1>

The clock consumer should specify the desired clock by having the clock ID in
its "clocks" phandle cell. The header efm32-clk.h contains a list of available
IDs.