Add clkng driver for Allwinner SoC

[manu]

Summary

This adds the ccung driver for Allwinner SoC.
Since Linux 4.9-4.10 DTS doesn't have clocks under /clocks but only a ccu node.
Currently only H3 is supported with almost the same state as HEAD. (video pll aren't supported for now but we don't support video).
This driver and clocks will also be used for other SoC (A64, A31, H5, H2 etc ...)

Test Plan

Tested on OrangePi One
cpufreq OK, ethernet OK, Thermal OK.
Audio isn't tested (no headphone on OrangePi).

[manu]

Only include ccu_h3.c is H3 SoC was selected.

[manu]

PLL_AUDIO factor n is 7 bit wide, not 6.

[manu]

Fix a few more mistakes in width of some factors.
It has been checked two times now but might need another pair of eyes.

[jmcneill]

sys/arm/allwinner/clkng/aw_ccung.c

287

We're going to need a way to make the SoC specific bits compile time options. No sense in having H3 support in a 64-bit kernel, for example.

sys/arm/allwinner/clkng/aw_clk_nkmp.c

159

This looks to be H3 specific.

233

if ((flags & CLK_SET_DRYRUN) != 0) {

and a few more below..

sys/arm/allwinner/clkng/aw_clk_nm.c

191

if ((sc->flags & AW_CLK_REPARENT) != 0) {

[manu]

sys/arm/allwinner/clkng/aw_ccung.c

287

RIght, I'll make it depend on ALLWINNER_SOC_XXX

sys/arm/allwinner/clkng/aw_clk_nkmp.c

159

I haven't finished/tested A31 but since I had the same lock problem when implementing cpufreq it might be needed there.

233

Yup sorry will correct that.

[manu]

Fix a few style(9) errors and only include H3 clk if SOC_ALLWINNER_H3 is selected.

[manu]

sys/arm/allwinner/clkng/aw_clk_nkmp.c

159

Confirmed, this is needed on A31 for cpufreq.

[jmcneill]

sys/arm/allwinner/clkng/aw_clk_nkmp.c

159

Are there plans for a10- and a23-style pll1 on clkng? According to arm/allwinner/clk/aw_pll.c these use nkmp style registers but do not require this change sequence.

[manu]

sys/arm/allwinner/clkng/aw_clk_nkmp.c

159

Then just don't set AW_CLK_SCALE_CHANGE and this will do the job.