Remove Message Signaled Interrupt support (for 2.6.16).
MSI is inherently edge-triggered and that is incompatiable (without more
work) with NAPI.

In future, will replace with smarter lockless-IRQ handling like
tg3.c
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>