This adds Rockchip RK3399 (e.g., Pine64 ROCKPro64) support:
- Ethernet works, ~500mbps. Can netboot like on RK3328 (ROCK64)
- I²C seems to work (rk805 PMIC driver (with 'rk808' name added) does not error)
- clocks/PLLs work
To actually reclock the CPU, extra hacks are required for now. (Basically, making cpufreq not require voltage control. On ROCKPro64, the default voltage is enough for the max clock. Actually the default voltage might be the highest one, since the heatsink gets rather hot when just idling in FreeBSD.)
To reclock properly, we'll need the rk8xx driver mentioned above. And, at least on the ROCKPro64, a driver for the "silergy,syr827" (aka "fcs,fan53555") which controls voltage for the big (Cortex-A72) cores. Other boards might use other chips for that voltage I guess.
(upd: trying to write that driver — the cpufreq isn't finding the regulator…)