rose: Set the destination address in rose_header

Not setting the destination address is a bug that I suspect causes no
problems today, as only the arp code seems to call dev_hard_header and
the description I have of rose is that it is expected to be used with a
static neigbour table.

I have derived the offset and the length of the rose destination address
from rose_rebuild_header where arp_find calls neigh_ha_snapshot to set
the destination address.

Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-hams@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>