initial cpu speed on orangepi one and orangepi pc2 - probably other H5 and H3 boards

[s_graf]

I just realized that the cpu speed on these boards defaults on start-up, the
pc2 to 816Mhz and the one to 1008 Mhz. Both of these machines should be able
to run at 1300Mhz.
The pc2 speed can be changed with hw.setperf, but not the one.
Can the sxiccmu module be changed to read a value from the dtb to use as the
initial cpu speed?