Update the mlx4 core and mlx4en(4) modules towards Linux v4.9.

Background:
The coming ibcore update forces an update of mlx4ib(4) which in turn requires
an updated mlx4 core module. This also affects the mlx4en(4) module because
commonly used APIs are updated. This commit is a middle step updating the
mlx4 modules towards the new ibcore.

This change contains no major new features.

Changes in mlx4:

a) Improved error handling when mlx4 PCI devices are
detached inside VMs.
b) Major update of codebase towards Linux 4.9.

Changes in mlx4ib(4):

a) Minimal changes needed in order to compile using the
updated mlx4 core APIs.

Changes in mlx4en(4):

a) Update flow steering code in mlx4en to use new APIs for
registering MAC addresses and IP addresses.
b) Update all statistics counters to be 64-bit.
c) Minimal changes needed in order to compile using the
updated mlx4 core APIs.

Sponsored by: Mellanox Technologies
MFC after: 1 week