It makes little sense but still possible to put Hyper-V guests into
suspend-to-idle state. To wake them up two wakeup sources were registered
in the past: hyperv-keyboard and hid-hyperv. However, since
commit eed4d47e ("ACPI / sleep: Ignore spurious SCI wakeups from
suspend-to-idle") pm_wakeup_event() from these devices is ignored. Switch
to pm_wakeup_hard_event() API as these devices are actually the only
possible way to wakeup Hyper-V guests.

Fixes: eed4d47e (ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle)
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>