mlx4_core: Stash PCI ID driver_data in mlx4_priv structure

[ No upstream commit, this is a cherry picked backport enabler. ]

That way we can check flags later on, when we've finished with the
pci_device_id structure.

This is a backport.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --cc drivers/net/ethernet/mellanox/mlx4/main.c
Simple merge

diff --cc drivers/net/ethernet/mellanox/mlx4/mlx4.h
Simple merge