staging: rtl8188eu: do not use comparisons on bool tests

This patch fixes coccinelle errors regarding comparisons
used in bool tests.

Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Reviewed-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>