common/mlx5: fix PCI driver name

common/mlx5: fix PCI driver name

In the refactor of mlx5 common layer, the PCI driver name to the RTE
device was changed from "net_mlx5" to "mlx5_pci". The string of name
"mlx5_pci" is used directly in the structure rte_pci_driver.

In the past, a macro "MLX5_DRIVER_NAME" is used instead of any direct
string, and now it is missing. The functions that use
"MLX5_DRIVER_NAME" will get some mismatch, e.g mlx5_eth_find_next.

It needs to use this macro again in all code to make everything get
aligned.

Fixes: 8a41f4deccc3 ("common/mlx5: introduce layer for multiple class drivers")
Cc: stable@dpdk.org
Signed-off-by: Bing Zhao <bingz@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>