CVE-2026-53105 wifi: mt76: mt7925: prevent NULL vif dereference in mt7925_mac_write_txwi

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7925: prevent NULL vif dereference in mt7925macwritetxwi Check for a NULL vif before accessing ieee80211vifismldvif to avoid a potential kernel panic in scenarios where vif might not be initialized...