net/mlx5_core: HW data structs/types definitions cleanup

mlx5_ifc.h was heavily modified here since it is now generated by a
script from the device specification (PRM rev 0.25). This specification
is backward compatible to existing hardware.

Some structures/fields were added here in order to enable the Ethernet
functionality of the driver.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>