MFC r289568, r300676, r300677, r300719, r300720 and r300721:
Implement LinuxKPI module parameters as SYSCTLs.

The bool module parameter is no longer supported, because there is no
equivalent in FreeBSD 10-stable. These are converted into "int" type.

There are two macros available which control the behaviour of the
LinuxKPI module parameters:

- LINUXKPI_PARAM_PARENT allows the consumer to set the SYSCTL parent
where the modules parameters will be created.

- LINUXKPI_PARAM_PREFIX defines a parameter name prefix, which is
added to all created module parameters.

The LinuxKPI module parameters also have a permissions value.
If any write bits are set we are allowed to modify the module
parameter runtime. Reflect this when creating the static SYSCTL
nodes.

The module_param_call() function is no longer supported.

Sponsored by: Mellanox Technologies

MFC r321782:
Remove some dead statistics related code and a structure field from the
mlx4en driver which is used by its Linux counterpart, but not under
FreeBSD.

Sponsored by: Mellanox Technologies

MFC r290710, r291694, r291699 and r291793:
- Fix print formatting compile warnings for Sparc64 and PowerPC platforms.
- Updated the mlx4 and mlxen drivers to the latest version, v2.1.6:
- Added support for dumping the SFP EEPROM content to dmesg.
- Fixed handling of network interface capability IOCTLs.
- Fixed race when loading and unloading the mlxen driver by applying
appropriate locking.
- Removed two unused C-files.
- Convert the mlxen driver to use the BUSDMA(9) APIs instead of
vtophys() when loading mbufs for transmission and reception. While at
it all pointer arithmetic and cast qualifier issues were fixed, mostly
related to transmission and reception.
- Fix i386 build WITH_OFED=YES. Remove some redundant KASSERTs.

Sponsored by: Mellanox Technologies
Differential Revision: https://reviews.freebsd.org/D4283
Differential Revision: https://reviews.freebsd.org/D4284

Merge r283612:
Add SIOCGI2C ioctl support to the driver. Would work only on ConnectX-3
with fresh firmware. The low level code is based on code provided by
Mellanox.

Thanks to Mellanox and their distributor Must (http://mustcompany.ru)
for providing hardware.

In collaboration with: Andre Melkoumian <andre mellanox.com>
Reviewed by: hselasky
Sponsored by: Netflix
Sponsored by: Nginx, Inc.

MFC r272027:

Hardware driver update from Mellanox Technologies, including:
- improved performance
- better stability
- new features
- bugfixes

Supported HCAs:
- ConnectX-2
- ConnectX-3
- ConnectX-3 Pro

NOTE:
- TSO feature needs r271946, which is not yet merged.

Sponsored by: Mellanox Technologies
Approved by: re, glebius

Merge r283612:
Add SIOCGI2C ioctl support to the driver. Would work only on ConnectX-3
with fresh firmware. The low level code is based on code provided by
Mellanox.

Thanks to Mellanox and their distributor Must (http://mustcompany.ru)
for providing hardware.

In collaboration with: Andre Melkoumian <andre mellanox.com>
Reviewed by: hselasky
Sponsored by: Netflix
Sponsored by: Nginx, Inc.

MFC r272027:

Hardware driver update from Mellanox Technologies, including:
- improved performance
- better stability
- new features
- bugfixes

Supported HCAs:
- ConnectX-2
- ConnectX-3
- ConnectX-3 Pro

NOTE:
- TSO feature needs r271946, which is not yet merged.

Sponsored by: Mellanox Technologies
Approved by: re, glebius