usb: add USB_RET_IOERROR

We already have USB_RET_NAK, but that means that a device does not want
to send/receive right now. But with host / network redirection we can
actually have a transaction fail due to some io error, rather then ie
the device just not having any data atm.

This patch adds a new error code named USB_RET_IOERROR for this, and uses
it were appropriate.

Notes:
-Currently all usb-controllers handle this the same as NODEV, but that
 may change in the future, OHCI could indicate a CRC error instead for example.
-This patch does not touch hw/usb-musb.c, that is because the code in there
 handles STALL and NAK specially and has a if status < 0 generic catch all
 for all other errors

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>