Convert wl_pointer::axis to wl_fixed_t

To go with the matching protocol change.

Signed-off-by: Daniel Stone <daniel@fooishbar.org>
diff --git a/clients/window.c b/clients/window.c
index f1f9176..9147da2 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -1813,7 +1813,7 @@
 
 static void
 pointer_handle_axis(void *data, struct wl_pointer *pointer,
-		    uint32_t time, uint32_t axis, int32_t value)
+		    uint32_t time, uint32_t axis, wl_fixed_t value)
 {
 }