qmp: include monitor.h when needed

This is needed to get file descriptors from SCM_RIGHTS.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
diff --git a/hmp.c b/hmp.c
index 2ce8cb9..b9cec1d 100644
--- a/hmp.c
+++ b/hmp.c
@@ -18,6 +18,7 @@
 #include "qemu-option.h"
 #include "qemu-timer.h"
 #include "qmp-commands.h"
+#include "monitor.h"
 
 static void hmp_handle_error(Monitor *mon, Error **errp)
 {