iwlwififw: add firmware for the Bz/B200 chipset

The iwlwifi driver already supports the chipset as "Bz TBD"
(also in 14.0). Add the firmware for it. Successfully tested
for 0x8086/0x272b/0x8086/0x00f4 on arm64 thanks to donated
hardware [1].

Firmware was obtained from linux-firmware at
9552083a783e5e48b90de674d4e3bf23bb855ab0 .

Sponsored by: The FreeBSD Foundation
Sponsored by: Martin Hoehne / minipci.biz (B200 card) [1]
MFC after: 3 days