staging: rtl8712: Simplify expressions with boolean logic

Simplify some expressions by using boolean operations.

Signed-off-by: Mauro Dreissig <mukadr@gmail.com>
Link: https://lore.kernel.org/r/20200705143552.9368-3-mukadr@gmail.com


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