ionic: fix a sleeping in atomic bug

This code is holding spin_lock_bh(&lif->rx_filters.lock); so the
allocation needs to be atomic.

Fixes: 969f8439

 ("ionic: sync the filters in the work task")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Link: https://lore.kernel.org/r/20210903131856.GA25934@kili
Signed-off-by: Jakub Kicinski <kuba@kernel.org>