PM / Runtime: Add sysfs switch for disabling device run-time PM

Add new device sysfs attribute, power/control, allowing the user
space to block the run-time power management of the devices.  If this
attribute is set to "on", the driver of the device won't be able to power
manage it at run time (without breaking the rules) and the device will
always be in the full power state (except when the entire system goes
into a sleep state).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 198b8f9..25b1eca 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -430,6 +430,7 @@
 	unsigned int		request_pending:1;
 	unsigned int		deferred_resume:1;
 	unsigned int		run_wake:1;
+	unsigned int		runtime_auto:1;
 	enum rpm_request	request;
 	enum rpm_status		runtime_status;
 	int			runtime_error;