hw/net/lasi_i82596: Re-enable build

When converting to the shiny build-system-du-jour, a typo prevented the
last_i82596 driver from being built. Correct the config option name to
re-enable the build. And include "sysemu/sysemu.h" so it actually builds.

Fixes: b1419fa66558 ("meson: convert hw/net")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2144
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Thomas Huth <thuth@redhat.com>
2 files changed