USB: let both new_id and remove_id show dynamic id list

This enables the current list of dynamic IDs to be read out through
either new_id or remove_id.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-usb

@@ -135,6 +135,17 @@ Description:
 		for the device and attempt to bind to it.  For example:
 		# echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id
 
+		Reading from this file will list all dynamically added
+		device IDs in the same format, with one entry per
+		line. For example:
+		# cat /sys/bus/usb/drivers/foo/new_id
+		8086 10f5
+		dead beef 06
+		f00d cafe
+
+		The list will be truncated at PAGE_SIZE bytes due to
+		sysfs restrictions.
+
 What:		/sys/bus/usb-serial/drivers/.../new_id
 Date:		October 2011
 Contact:	linux-usb@vger.kernel.org
@@ -157,6 +168,10 @@ Description:
 		match the driver to the device.  For example:
 		# echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id
 
+		Reading from this file will list the dynamically added
+		device IDs, exactly like reading from the entry
+		"/sys/bus/usb/drivers/.../new_id"
+
 What:		/sys/bus/usb/device/.../avoid_reset_quirk
 Date:		December 2009
 Contact:	Oliver Neukum <oliver@neukum.org>