staging: rtl8188eu: remove useless include

Since the removal of rtw_proc_init_one() the proc filesystem is not
mentioned in this driver. So this include becomes useless.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Binoy Jayan <binoy.jayan@linaro.org>
Cc: Anish Bhatt <anish@gatech.edu>
Cc: "Rémy Oudompheng" <remyoudompheng@gmail.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Kyle Kuffermann <kyle.kuffermann@gmail.com>
Cc: devel@driverdev.osuosl.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>