linux-phytec-ti

USB: cdc-acm: clean up dev_err and dev_dbg

Clean up some dev_err and dev_dbg messages and make sure that the
appropriate interface device is used for reporting consistently
throughout.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>