net: hsr: Use the seqnr lock for frames received via interlink port.

net: hsr: Use the seqnr lock for frames received via interlink port.

syzbot reported that the seqnr_lock is not acquire for frames received
over the interlink port. In the interlink case a new seqnr is generated
and assigned to the frame.
Frames, which are received over the slave port have already a sequence
number assigned so the lock is not required.

Acquire the hsr_priv::seqnr_lock during in the invocation of
hsr_forward_skb() if a packet has been received from the interlink port.

Reported-by: syzbot+3d602af7549af539274e@syzkaller.appspotmail.com
Closes: https://groups.google.com/g/syzkaller-bugs/c/KppVvGviGg4/m/EItSdCZdBAAJ
Fixes: 5055cccfc2d1c ("net: hsr: Provide RedBox support (HSR-SAN)")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Tested-by: Lukasz Majewski <lukma@denx.de>
Link: https://patch.msgid.link/20240906132816.657485-2-bigeasy@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>