staging: r8188eu: remove hal_reset_security_engine member of hal_ops structure

hal_reset_security_engine always is NULL.
Also rtw_hal_reset_security_engine function removed.

Signed-off-by: Ivan Safonov <insafonov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>