staging: rtl8723au: Clean up usb_{read,write}_port() usage

Get rid of silly HAL convolution for calling usb_{read,write}_port()
functions.

Benefit from fact we just have one input address for read_port, so no
point storing this and carrying it around.

Pick pipe in the local function instead of based on dst/src address.

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