MFC: r308728, r314369, r315243, r316026, r316581, r316616, r318359,
r319922, r319990, r321481, r323232-323233, r323321, r323874, r323955,
r324323, r324964, r325169, r325488, r325620, r326985, r326999-327001,
r327003, r329335

Update bnxt to latest -CURRENT.

Approved by: re (gjb@)
Differential Revision: https://reviews.freebsd.org/D15143

MFC r308696, r308729, r308787, r308813, r309028, r309073, r309078:

r308696:
New driver for Broadcom NetXtreme-C and NetXtreme-E devices.

r308729:
Add bnxt(4) to the hardware notes.

r308787:
Add missing newline in error mesage

r308813:
Check link status after init

r309028:
Add missing break to switch statement

r309073:
Fix version string

r309078:
Add new device IDs

Approved by: sbruno
Relnotes: yes
Sponsored by: Broadcom Limited

New driver for Broadcom NetXtreme-C and NetXtreme-E devices.

This driver uses the iflib framework supporting Broadcom
25/50Gbps devices.

Reviewed by: gallatin, wblock
Approved by: davidch
MFC after: 2 weeks
Relnotes: yes
Sponsored by: Broadcom Limited
Differential Revision: https://reviews.freebsd.org/D7551