staging: rtl8192u: Using comparison to true is error prone

clear below issues reported by checkpatch.pl:

CHECK: Using comparison to false is error prone

Signed-off-by: John Oldman <john.oldman@polehill.co.uk>
Link: https://lore.kernel.org/r/20200706162240.2770-1-john.oldman@polehill.co.uk


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