windows: Rename find_oldest_window to windows_find_oldest

Change-Id: I7b76fc57b6b1002c195af86167ae4fa6fd99489c
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/windows.h b/windows.h
index 943ea9b..3cb2a52 100644
--- a/windows.h
+++ b/windows.h
@@ -25,7 +25,7 @@
 			  uint8_t flags);
 void window_reset(struct mbox_context *context, struct window_context *window);
 void windows_reset_all(struct mbox_context *context, bool set_bmc_event);
-struct window_context *find_oldest_window(struct mbox_context *context);
+struct window_context *windows_find_oldest(struct mbox_context *context);
 struct window_context *find_largest_window(struct mbox_context *context);
 struct window_context *search_windows(struct mbox_context *context,
 				      uint32_t offset, bool exact);