staging: r8188eu: set pipe only once

Set the pipe for reading or writing in usbctrl_vendorreq only once.
There's no need to set it again for every retry.

This patch is an adaptation of commit 889ed8b5 ("staging: rtl8188eu:
set pipe only once") for the new r8188eu driver.

Acked-by: Phillip Potter <phil@philpotter.co.uk>
Acked-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210821164859.4351-10-martin@kaiser.cx


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