Add qcaoss(4), a driver for the Always On Subsystem found on Qualcomm SoCs.

Add qcaoss(4), a driver for the Always On Subsystem found on Qualcomm SoCs.

This subsystem typically provides an interface for clocks and regulators
not controlled via RPMH.  We will use it to switch the load state of the
ADSP co-processor.  Surprisingly, or maybe not, the interface uses ASCII
text that kind of looks like JSON.

ok kettenis@