net/mlx5: remove declaration duplications
net/mlx5: remove declaration duplications

In mlx5_ethdev.c file are implemented those 4 functions:
 - mlx5_dev_infos_get
 - mlx5_fw_version_get
 - mlx5_dev_set_mtu
 - mlx5_hairpin_cap_get

In mlx5.h file they are declared twice. First time under mlx5.c file and
second time under mlx5_ethdev.c file.

This patch removes the redundant declaration.

Signed-off-by: Michael Baum <ea5d219418f4ca0051d96051b5f634ca452be1f3@nvidia.com>
Acked-by: Matan Azrad <6969f5f553ad7652679a585a85d7321babc90464@nvidia.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk