WPA3 SAE is not supported on Pi 400 (BCM43456)

Start by examining the brcmfmac BCM43456 support and the brcm/brcmfmac43456-sdio firmware path, comparing them with the BCM43455 support referenced in the report. Reproduce the capability checks with iw phy and wpa_cli get_capability key_mgmt; done would be WPA3-Personal SAE being reported and usable on Raspberry Pi 400.

Describe the bug

WPA3-Personal SAE Wi-Fi standard doesn't seem to be supported by the firmware/driver of Raspberry Pi 400.
The 400 has BCM43456 module (brcm/brcmfmac43456-sdio firmware), compared to Pi 3B/4/5, which use SYM43455 (cypress/cyfmac43455-sdio firmware).

So far there were issues here and on forum, firmware and code updates from Infineon for 43455 only as far as I could see.
Raspberry Pi 400 on the latest official OS version does not report anything related to SAE in iw phy, as well as wpa_cli get_capability key_mgmt.

Connecting to WPA3-Personal Only networks on Raspberry Pi 400 does not work.

Steps to reproduce the behaviour

Try to connect to WPA3-Personal Only network using Rasberry Pi 400

Device (s)

Raspberry Pi 400

System

6.18.39+rpt-rpi-v8

Logs

$ dmesg | grep 4345
[    8.809313] Bluetooth: hci0: BCM4345C5
[    8.809321] Bluetooth: hci0: BCM4345C5 (003.006.006) build 0000
[    8.938140] brcmfmac: F1 signature read @0x18000000=0x15294345
[    8.941616] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43456-sdio for chip BCM4345/9
[    8.980155] Bluetooth: hci0: BCM4345C5 'brcm/BCM4345C5.raspberrypi,400.hcd' Patch
[    9.212095] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM4345/9 wl0: May 14 2020 17:26:08 version 7.84.17.1 (r871554) FWID 01-3d9e1d87
[    9.714776] Bluetooth: hci0: BCM43456 37.4MHz Raspberry Pi BT5.0 [Version: 1052.1108]
[    9.714782] Bluetooth: hci0: BCM4345C5 (003.006.006) build 1108


$ iw phy | grep -i sae || echo empty!
empty!

$ wpa_cli get_capability key_mgmt
NONE IEEE8021X WPA-EAP WPA-PSK WPA-EAP-SUITE-B OWE DPP FT-PSK FT-EAP
(no sae)

$ wpa_cli get_capability auth_alg
OPEN SHARED LEAP
(no sae)