include/user/guest-host: Include missing cpu.h

This file dereferences CPUState without including the required header.

Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

include/user/guest-host.h

@@ -10,6 +10,7 @@
 
 #include "exec/vaddr.h"
 #include "user/guest-base.h"
+#include "hw/core/cpu.h"
 #include "accel/tcg/cpu-ops.h"
 
 /*