ionic: change set_rx_mode from_ndo to can_sleep

Instead of having two different ways of expressing the same
sleepability concept, using opposite logic, we can rework the
from_ndo to can_sleep for a more consistent usage.

Fixes: 1800eee1

 ("net: ionic: Replace in_interrupt() usage.")
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>