mt76x2: fix possible NULL pointer dereferencing in mt76x2_tx()
Fix a theoretical NULL pointer dereferencing in mt76x2_tx routine that
can occurs for injected frames in a monitor vif since vif pointer could
be NULL for that interfaces
Fixes: 23405236460b ("mt76: fix transmission of encrypted mgmt frames") Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Acked-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>