HEADSUP: apm(4) driver synced with current

[John Baldwin]

In order to support the eventual MFC of a limited and experimental acpi(4)
driver from -CURRENT, I have merged a few changes from -CURRENT to -STABLE
including:

- Power management interface (subr_power.c)
- pmtimer(4) driver.  Unlike -CURRENT this driver does not require
  'device pmtimer' in the kernel config so that existing kernel configs
  do not have to be changed.
- Updated suspend/resume code in the i386 interrupt and clock code.
- APM driver updated for the above changes (includes syncing with
  -CURRENT)

There should be no regression in APM functionality.  If there is, please
let myself and re@ know.  Working APM in 4.9-RELEASE is more important
than experimental ACPI support.

Thanks.

-- 

John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/