Fix io-thread build breakage of a88790a1

Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

cpus.c

@@ -30,6 +30,7 @@
 #include "gdbstub.h"
 #include "dma.h"
 #include "kvm.h"
+#include "exec-all.h"
 
 #include "cpus.h"