MFC r356485-r356486, r356893, r358278-r358279

r356485:
rk808: Add min/max for the switch regulators

The two switch regulator are always 3.0V.
Add a special case in get_voltage that if min=max we directly
return the value without calculating it.

Reviewed by: mmel
Differential Revision: https://reviews.freebsd.org/D23004

r356486:
rk805: Add regnode_status method

This allow consumers to check if the regulator is enable or not.

Reviewed by: mmel
Differential Revision: https://reviews.freebsd.org/D23005

r356893:
rk805: Add a regnode_init method

This method will set the desired voltaged based on values in the DTS.
It will not enable the regulator, this is the job of either a consumer
or regnode_set_constraint SYSINIT if the regulator is boot_on or always_on.

Reviewed by: mmel
Differential Revision: https://reviews.freebsd.org/D23216

r358278:
arm64: rockchip: rk_i2c: Bump to DELAY to 1000

In polling mode with use DELAY to wait for interrupts. The value was
too low for RK3328.

r358279:
arm64: rockchip: rk808: Only init regulator not enabled

If a regulator is already enabled, do not set its value to the minimum
supported on the board.
This fixes booting on rock64 where we set some regulator to the minimal value
while the IPs needs more based on what the bootloader configured.