NetBSD guest only supports network without ACPI

Git commit: abdfd9500e07fab7d6ffd4385fa30a065c329a39
Host: Linux 64bit Debian
Guest: NetBSD5.0.2/i386

Networking works only when ACPI is disabled in the guest. Without it the network card (wm0) is not detected.

Boot: qemu -hda netbsd5.0.2-i386 -boot c -enable-kvm
Configure: --enable-linux-aio --enable-io-thread --enable-kvm