softmmu: fix crash with invalid -M memory-backend=

Fixes: fe64d06afc1c5d895f220c268cfe4d5f1e65d44e ("vl.c: ensure that
ram_size matches size of machine.memory-backend")
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200309145155.168942-1-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 file changed