staging: rtl8188eu: remove unused dump_txrpt_ccx_88e()

The function dump_txrpt_ccx_88e() is nerver used, so remove it.
Discovered by cppcheck.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>