staging: r8188eu: fix coccinelle warnings

drivers/staging/rtl8188eu/core/rtw_mlme_ext.c:8030:3-9: Replace memcpy with struct assignment

Generated by: coccinelle/misc/memcpy-assign.cocci

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>