net/mlx5e: Mark enabled RQTs instances explicitly

In the current driver implementation two types of receive queue
tables (RQTs) are in use - direct and indirect.

Change the driver to mark each new created RQT (direct or indirect)
as "enabled". This behaviour is needed for introducing new mlx5e
instances which serve to represent SRIOV VFs.

The VF representors will have only one type of RQTs (direct).

An "enabled" flag is added to each RQT to allow better handling
and code sharing between the representors and the nic netdevices.

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>