USB: add USB test and measurement class driver

This driver was originaly written by Stefan Kopp, but massively
reworked by Greg for submission.

Thanks to Felipe Balbi <me@felipebalbi.com> for lots of work in cleaning
up this driver.

Thanks to Oliver Neukum <oliver@neukum.org> for reviewing previous
versions and pointing out problems.


Cc: Stefan Kopp <stefan_kopp@agilent.com>
Cc: Marcel Janssen <korgull@home.nl>
Cc: Felipe Balbi <me@felipebalbi.com>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/devices.txt b/Documentation/devices.txt
index 05c8064..2be0824 100644
--- a/Documentation/devices.txt
+++ b/Documentation/devices.txt
@@ -2571,6 +2571,9 @@
 		160 = /dev/usb/legousbtower0	1st USB Legotower device
 		    ...
 		175 = /dev/usb/legousbtower15	16th USB Legotower device
+		176 = /dev/usb/usbtmc1	First USB TMC device
+		   ...
+		192 = /dev/usb/usbtmc16	16th USB TMC device
 		240 = /dev/usb/dabusb0	First daubusb device
 		    ...
 		243 = /dev/usb/dabusb3	Fourth dabusb device