ACPI / ACPICA: Implicit notify for multiple devices

Commit bba63a2 (ACPICA: Implicit notify support) introduced a
mechanism that causes a notify request of type
ACPI_NOTIFY_DEVICE_WAKE to be queued automatically by
acpi_ev_asynch_execute_gpe_method() for the device whose _PRW points
to the GPE being handled if that GPE is not associated with an
_Lxx/_Exx method.  However, it turns out that on some systems there
are multiple devices with _PRW pointing to the same GPE without
_Lxx/_Exx and the mechanism introduced by commit bba63a2 needs to be
extended so that "implicit" notify requests of type
ACPI_NOTIFY_DEVICE_WAKE can be queued automatically for all those
devices at the same time.

Reported-and-tested-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/acpi/acpica/aclocal.h b/drivers/acpi/acpica/aclocal.h
index 54784bb..edc2586 100644
--- a/drivers/acpi/acpica/aclocal.h
+++ b/drivers/acpi/acpica/aclocal.h
@@ -416,10 +416,15 @@
 	u8 originally_enabled;  /* True if GPE was originally enabled */
 };
 
+struct acpi_gpe_notify_object {
+	struct acpi_namespace_node *node;
+	struct acpi_gpe_notify_object *next;
+};
+
 union acpi_gpe_dispatch_info {
 	struct acpi_namespace_node *method_node;	/* Method node for this GPE level */
 	struct acpi_gpe_handler_info *handler;  /* Installed GPE handler */
-	struct acpi_namespace_node *device_node;        /* Parent _PRW device for implicit notify */
+	struct acpi_gpe_notify_object device;   /* List of _PRW devices for implicit notify */
 };
 
 /*