qapi: move inclusions of qemu-common.h from headers to .c files

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/tests/test-string-input-visitor.c b/tests/test-string-input-visitor.c
index 5370e32..36b3792 100644
--- a/tests/test-string-input-visitor.c
+++ b/tests/test-string-input-visitor.c
@@ -13,6 +13,7 @@
 #include <glib.h>
 #include <stdarg.h>
 
+#include "qemu-common.h"
 #include "qapi/string-input-visitor.h"
 #include "test-qapi-types.h"
 #include "test-qapi-visit.h"