Move qemu-timer.h to include/qemu/timer.h

Note: upstream still puts qemu-timer.c in the top-level
directory, so no need to move it

Change-Id: I475309d6f0040b4fd2277e52a2526825c112e91f
diff --git a/usb-dummy-android.c b/usb-dummy-android.c
index ed03219..903e398 100755
--- a/usb-dummy-android.c
+++ b/usb-dummy-android.c
@@ -23,7 +23,7 @@
  */
 
 #include "qemu-common.h"
-#include "qemu-timer.h"
+#include "qemu/timer.h"
 #include "monitor.h"
 #include "hw/usb.h"