rk805: add system poweroff support

[avg]

Summary

On my Rock64 neither EFI nor PSCI shutdown actually power off the board.
RK805 does the job.

[manu]

It's also compatible with rk808 so perfect.

[imp]

sys/arm64/rockchip/rk805.c

865

This cast isn't needed, and could be combined with the device_t dev declaration above.

867

shutdown or power off here?

874

and you don't need two sets of elipses.

945

Why override? Is there some advantage to not trying those methods first?

[avg]

sys/arm64/rockchip/rk805.c

865

I just copied the predominant style in the file.
But I agree.

867

Both should mean the same in this context.

874

But this is printed (if printed at all) on a separate line.

945

Yes. See the summary / commit message.
Maybe it's not entirely clear, but both of those methods not only fail to power off, but they also get stuck until the software watchdog panic-s the system (or invokes ddb).

[imp]

sys/arm64/rockchip/rk805.c

867

Except all the other power-off functions in the system say 'power off' because 'shutdown' often means 'while(1);' or similar loop at the end, at least historically.

874

true. You can ignore this.

945

Add add that here explicitly. It's important enough to not be buried in the commit message, I'd think.

[avg]

address reviews for rk805 poweroff support

Also, rename the shutdown function to poweroff so that it is not
confused with the device_shutdown method.
Always print the "powering off" message (liberate from bootverbose).
If the code still runs after issuing the power-off command then it
failed regardless of whether we had any errors or not.

[kjopek_gmail.com]

Works nice on my RockPro64 board. Thanks!