[PATCH] Altix: shut off xmit intr if done xmitting

Small mod to shut off the xmit interrupt if we have nothing to transmit.

Signed-off-by: Patrick Gefre <pfg@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>