net: mctp: usb: don't fail mctp_usb_rx_queue on a deferred submission

net: mctp: usb: don't fail mctp_usb_rx_queue on a deferred submission

In the ndo_open path, a deferred queue open will report a failure, and
so the netdev will not be ndo_stop()ed, leaving us with the rx_retry
work potentially pending.

Don't report a deferred queue as an error, as we are still operational.
This means we use the ndo_stop() path for future cleanup, which handles
rx_retry_work cancellation.

Fixes: 0791c0327a6e ("net: mctp: Add MCTP USB transport driver")
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260608-dev-mctp-usb-rx-requeue-v2-2-29a3aa507609@codeconstruct.com.au
Signed-off-by: Paolo Abeni <pabeni@redhat.com>