staging: rtl8188eu: cleanup long line in rtw_mlme_ext.c

Remove comparsion to NULL and unnecessary parentheses to avoid line
length over 80 characters and follow kernel coding style.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20190912114257.17529-1-straube.linux@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>