Change Kconfig description

This patch apply Mellanox network vendor which includes:
- Mellanox card devices: ConnectX-4, ConnectX-5 and Connect-IB cards.
- Mellanox switch device: SwitchX-2 Switch-IB, Spectrum.
Therefore rephrasing help.

Signed-off-by: Ohad Oz <ohado@mellanox.com>
Acked-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>