wifi-scripts: ucode: add WPA3-Personal Compatibility Mode

wifi-scripts: ucode: add WPA3-Personal Compatibility Mode

The WPA3 and Wi-Fi Enhanced Open Deployment and Implementation Guide
v1.1 §2.4 (Tables 6 and 7) defines WPA3-Personal Compatibility Mode:
the AP advertises a legacy-looking RSNE (WPA-PSK, CCMP-128, PMF
Disabled) while RSN Override Elements layered on top expose SAE and,
on EHT, SAE-EXT-KEY.  WPA2-only STAs and STAs that ignore RSN
Overriding associate unchanged; modern STAs pick up the stronger WPA3
AKM via RSNOE or RSNO2E.

Only the pairwise cipher differs between elements: RSNE and RSNOE
advertise CCMP-128, RSNO2E advertises GCMP-256 (EHT only).  Group
data (CCMP-128) and group management cipher (BIP-CMAC-128) are the
same in all three per Tables 6/7, so hostapd's BSS-wide group_cipher
and group_mgmt_cipher singletons produce the spec-correct values.

Unlike WPA3-Personal Transition Mode (sae-mixed), which puts PSK and
SAE together in the main RSNE with PMF Capable, Compatibility Mode
keeps the main RSNE strictly WPA2-shaped so clients that choke on a
mixed AKM list or PMF=Capable still see a pure WPA2 BSS.  The trade-
off is that clients without RSN Overriding support never pick up SAE.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Link: https://github.com/openwrt/openwrt/pull/23009
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>