[ROSE]: ROSE has no ARP

ARP over ROSE does not exist so it's obviously not implemented on any
ROSE stack, so the ROSE interfaces really should default to IFF_NOARP.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>