staging: r8188eu: remove unnecessary parentheses

Remove unnecessary parentheses around a variable to improve
readability.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210830121508.6411-9-straube.linux@gmail.com


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