staging: r8188eu: remove unneeded conversions to bool

staging: r8188eu: remove unneeded conversions to bool

Found with scripts/coccinelle/misc/boolconv.cocci.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Reviewed-by: Pavel Skripkin <paskripkin@gmail.com>
Acked-by: Michael Straube <straube.linux@gmail.com>
Acked-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Jing Yangyang <jing.yangyang@zte.com.cn>
Link: https://lore.kernel.org/r/20210824063443.59724-1-deng.changcheng@zte.com.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>