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

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index 7a82b63..3002939 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -11,6 +11,7 @@
  *
  */
 
+#include "qemu-common.h"
 #include "qapi/qapi-visit-core.h"
 #include "qapi/qapi-visit-impl.h"