vdpa/mlx5: fix PCI address comparison

vdpa/mlx5: fix PCI address comparison

A regular memcmp function was used to compare between two objects of
type `struct rte_pci_addr`.

Due to the alignment rules of compiler structure builders, some memory
is not initiated in the structure even though all the fields were
initiated.

Therefore, the comparison may fail even though the PCI addresses are
identical and to cause false failure in probe.

Use the dedicated API to compare 2 PCI addresses.

Fixes: 75dd0ae91765 ("vdpa/mlx5: disable RoCE")
Cc: stable@dpdk.org
Signed-off-by: Matan Azrad <matan@mellanox.com>
Tested-by: Noa Ezra <noae@mellanox.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>