The Thinkpad e530's BIOS notifies the AC device first and then
sleeps for certain amount of time before doing real work in the
EC event handler (_Qxx):

 Method (_Q27, 0, NotSerialized)
 {
       Notify (AC, 0x80)
       Sleep (0x03E8)
       Store (Zero, PWRS)
       PNOT ()
 }

This causes the AC driver to report an outdated AC state to user
space, because it reads the state information from the device while
the EC handler is sleeping.

Introduce a quirk to cause the AC driver to wait in acpi_ac_notify()
before calling acpi_ac_get_state() on systems known to have this
problem and add Thinkpad e530 to the list of quirky machines (with
a 1s delay which has been verified to be sufficient for that
machine).

[rjw: Changelog]
References: https://bugzilla.kernel.org/show_bug.cgi?id=45221


Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>