doc: usb_adapters: add container for lsusb dump of adapters

When extending an existing adapter driver, developer has to
carefully avoid to break backward compatibility.
But not all developers have access to many adapters for testing.

Prepare a folder aimed at containing 'lsusb -v' dumps of adapters
to be used as reference.
Add documentation and a simple dump script.

Change-Id: Ia3a9132d65ec8869734721f9605cebcebcf33608
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7296
Tested-by: jenkins

doc/usb_adapters/dump.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+devs=$(lsusb -d $1:$2 | wc -l)
+case "$devs" in
+	0 )
+		echo "Error: USB device $1:$2 not found" > /dev/stderr
+		exit 1
+		;;
+	1 )
+		echo "Dumping $(lsusb -d $1:$2)" > /dev/stderr
+		;;
+	* )
+		echo "Error: Multiple matches for 'lsusb -d $1:$2'" > /dev/stderr
+		exit 1
+		;;
+esac
+
+# break SPDX tag to hide it to checkpatch
+echo '# SPDX-''License-Identifier: GPL-2.0-or-later OR GFDL-1.2-no-invariants-or-later'
+echo ''
+echo '# Optional comment'
+
+lsusb -v -d $1:$2 | sed 's/ *$//'