thunderbolt: Mention Thunderbolt/USB4 debugging tools in Kconfig

This allows the interested parties to find the Thunderbolt/USB4
debugging tools (aka tbtools) easier in case they need to look at the
information under debugfs entries.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Suggested-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

drivers/thunderbolt/Kconfig

@@ -22,7 +22,11 @@ config USB4_DEBUGFS_WRITE
 	bool "Enable write by debugfs to configuration spaces (DANGEROUS)"
 	help
 	  Enables writing to device configuration registers through
-	  debugfs interface.
+	  debugfs interface. You can use tools such as Thunderbolt/USB4
+	  debugging tools to access these registers. For more
+	  information see:
+
+	    https://github.com/intel/tbtools
 
 	  Only enable this if you know what you are doing! Never enable
 	  this for production systems or distro kernels.