staging: rtl8723au: Do not use comparisons on bool tests

This patch removes unnecessary comparisons to bool.
It fixes the following warning detected using coccinelle tool:
WARNING: Comparison to bool.

Signed-off-by: Roberta Dobrescu <roberta.dobrescu@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>