[DECNET]: Fix sfuzz hanging on 2.6.18

Dave Jones wrote:
> sfuzz         D 724EF62A  2828 28717  28691                     (NOTLB)
>        cd69fe98 00000082 0000012d 724ef62a 0001971a 00000010 00000007 df6d22b0
>        dfd81080 725bbc5e 0001971a 000cc634 00000001 df6d23bc c140e260 00000202
>        de1d5ba0 cd69fea0 de1d5ba0 00000000 00000000 de1d5b60 de1d5b8c de1d5ba0
> Call Trace:
>  [<c05b1708>] lock_sock+0x75/0xa6
>  [<e0b0b604>] dn_getname+0x18/0x5f [decnet]
>  [<c05b083b>] sys_getsockname+0x5c/0xb0
>  [<c05b0b46>] sys_socketcall+0xef/0x261
>  [<c0403f97>] syscall_call+0x7/0xb
> DWARF2 unwinder stuck at syscall_call+0x7/0xb
>
> I wonder if the plethora of lockdep related changes inadvertantly broke something?

Looks like unbalanced locking.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>