jme: Protect vlgrp structure by pause RX actions.

Temporary stop the RX IRQ, and disable (sync) tasklet or napi.
And restore it after finished the vlgrp pointer assignment.

Signed-off-by: Guo-Fu Tseng <cooldavid@cooldavid.org>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>