net/mlx5e: Add support for RXFCS feature flag

Add support for rx-fcs flag from ethtool.
In case this flag is set, update all RQs to scatter the FCS data into
the packet.

Signed-off-by: Guy Ergas <guye@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>