io: Clean up includes

Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1454089805-5470-14-git-send-email-peter.maydell@linaro.org
diff --git a/io/channel-buffer.c b/io/channel-buffer.c
index daebc92..0f7c567 100644
--- a/io/channel-buffer.c
+++ b/io/channel-buffer.c
@@ -18,6 +18,7 @@
  *
  */
 
+#include "qemu/osdep.h"
 #include "io/channel-buffer.h"
 #include "io/channel-watch.h"
 #include "qemu/sockets.h"