wifi: mt76: mt7996: drop fragments with multicast or broadcast RA

IEEE 802.11 fragmentation can only be applied to unicast frames.
Therefore, drop fragments with multicast or broadcast RA. This patch
addresses vulnerabilities such as CVE-2020-26145.

Signed-off-by: Benjamin Lin <benjamin-jw.lin@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Link: https://patch.msgid.link/20250515032952.1653494-4-shayne.chen@mediatek.com


Signed-off-by: Felix Fietkau <nbd@nbd.name>