net: fec: Avoid allocating rx buffer using ATOMIC in ndo_open

Make ndo_open less sensitive to memory pressure.

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20220518062007.10056-1-michael@amarulasolutions.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>