hsr: Fix uninit-value access in fill_frame_info()

In the Linux kernel, the following vulnerability has been resolved:

hsr: Fix uninit-value access in fill_frame_info()

Syzbot reports the following uninit-value access problem.

=====================================================
BUG: KMSAN: uninit-value in fill_frame_info net/hsr/hsr_forward.c:601 [inline]
BUG: KMSAN: uninit-value in hsr_forward_skb+0x9bd/0x30f0 net/hsr/hsr_forward.c:616
fill_frame_info net/hsr/hsr_forward.c:601 [inline]
hsr_forward_skb+0x9bd/0x30f0 net/hsr/hsr_forward.c:616
hsr_dev_xmit+0x192/0x330 net/hsr/hsr_device.c:223
__netdev_start_xmit include/linux/netdevice.h:4889 [inline]
netdev_start_xmit include/linux/netdevice.h:4903 [inline]
xmit_one net/core/dev.c:3544 [inline]
dev_hard_start_xmit+0x247/0xa10 net/core/dev.c:3560
__dev_queue_xmit+0x34d0/0x52a0 net/core/dev.c:4340
dev_queue_xmit include/linux/netdevice.h:3082 [inline]
packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
packet_snd net/packet/af_packet.c:3087 [inline]
packet_sendmsg+0x8b1d/0x9f30 net/packet/af_packet.c:3119
sock_sendmsg_nosec net/socket.c:730 [inline]
sock_sendmsg net/socket.c:753 [inline]
__sys_sendto+0x781/0xa30 net/socket.c:2176
__do_sys_sendto net/socket.c:2188 [inline]
__se_sys_sendto net/socket.c:2184 [inline]
__ia32_sys_sendto+0x11f/0x1c0 net/socket.c:2184
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
do_fast_syscall_32+0x37/0x80 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82

Uninit was created at:
slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
slab_alloc_node mm/slub.c:3478 [inline]
kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523
kmalloc_reserve+0x148/0x470 net/core/skbuff.c:559
__alloc_skb+0x318/0x740 net/core/skbuff.c:644
alloc_skb include/linux/skbuff.h:1286 [inline]
alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6299
sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2794
packet_alloc_skb net/packet/af_packet.c:2936 [inline]
packet_snd net/packet/af_packet.c:3030 [inline]
packet_sendmsg+0x70e8/0x9f30 net/packet/af_packet.c:3119
sock_sendmsg_nosec net/socket.c:730 [inline]
sock_sendmsg net/socket.c:753 [inline]
__sys_sendto+0x781/0xa30 net/socket.c:2176
__do_sys_sendto net/socket.c:2188 [inline]
__se_sys_sendto net/socket.c:2184 [inline]
__ia32_sys_sendto+0x11f/0x1c0 net/socket.c:2184
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
do_fast_syscall_32+0x37/0x80 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82

It is because VLAN not yet supported in hsr driver. Return error
when protocol is ETH_P_8021Q in fill_frame_info() now to fix it.