greybus: Documentation: remove svc unique_id attribute

Remove unimplemented svc unique_id attribute from the documentation.

This attribute made more sense when we thought we'd have an AP-module,
unlike now when the AP and SVC are both part of the same frame.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/Documentation/sysfs-bus-greybus

@@ -150,13 +150,6 @@ Description:
 		Write the number of the interface that you wish to
 		forcibly eject from the system.
 
-What:		/sys/bus/greybus/device/N-svc/unique_id
-Date:		October 2015
-KernelVersion:	4.XX
-Contact:	Greg Kroah-Hartman <greg@kroah.com>
-Description:
-		The unique ID, or serial number, of the SVC device
-
 What:		/sys/bus/greybus/device/N-svc/version
 Date:		October 2015
 KernelVersion:	4.XX