staging: rtl8723au: hal/usb_ops_linux.c: Various cleanups

Reduce excessive parenthesis usage, remove unnecessary null
initialization of variables, and some bad formatting.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>