net/mlx5e: Create NIC global resources only once

To allow creating more than one netdev over the same PCI function, we
change the driver such that global NIC resources are created once and
later be shared amongst all the mlx5e netdevs running over that port.

Move the CQ UAR, PD (pdn), Transport Domain (tdn), MKey resources from
being kept in the mlx5e priv part to a new resources structure
(mlx5e_resources) placed under the mlx5_core device.

This patch doesn't add any new functionality.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>