Add support for Rock Pi

[cyphunk]

Power power consumption, better availability

https://www.thanassis.space/rockpis.html

Putting my USB power meter in the loop, I measured the current going in. During boot, this spiked up to around 300mA - and then settled down in idle, to around 80mA.
Put differently: 0.08A x 5V = 0,4W. 400mWatt!
Very impressive!... Things have really changed since I last measured this; I didn't keep a detailed journal like I did for this board, but I believe the Orange PI Zero was somewhere around 250mA - more than 3 times this little guy.
As for the consumption during the other benchmarks:
when stress-testing with my renderer loading all CPUs at 100% and fully using the floating point unit on all of them, the current consumption reached a ceiling of 370mA. Simply put, the maximum consumption I managed to force on the ROCK PI S, was a bit less than 2W.
When maximising the USB bus usage with dd from an external 1TB drive, the current consumption topped at 150mA (0.75W)