staging: rtl8723bs: Remove unnecessary parentheses

This patch removes unnecessary parentheses.
Issue found by checkpatch
Signed-off-by: Javier F. Arias <jarias.linux@gmail.com>
Link: https://lore.kernel.org/r/b2526b464b8afed3b2c3a3a72ae183fb63df3ae7.1572734925.git.jarias.linux@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>