Staging: cpc-usb: add one todo entry

we need to get rid of those driver-specific error codes
Signed-off-by: Felipe Balbi <me@felipebalbi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/cpc-usb/TODO

@@ -5,5 +5,6 @@ kernel:
 	- remove proc code
 	- tie into CAN socket interfaces if possible
 	- figure out sane userspace api
+	- use linux's error codes
 
 Send patches to Greg Kroah-Hartman <greg@kroah.com>