RDMA/mlx5: Update mlx5_ib driver name

Current description doesn't include new devices, change it by updating to
have more generic description and remove DRIVER_NAME and DRIVER_VERSION
defines.

Link: https://lore.kernel.org/r/20200513095304.210240-1-leon@kernel.org
Signed-off-by: Shay Drory <shayd@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>