zink: Use memmove when dealing with overlapping memory

Fix defect reported by Coverity Scan.

Overlapping buffer in memory copy

Results in an undefined behavior

CID: 1515598

Signed-off-by: Corentin Noël <corentin.noel@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26922>

src/gallium/drivers/zink/zink_clear.c

@@ -234,7 +234,7 @@ zink_clear(struct pipe_context *pctx,
                    */
                   add_new_clear(fb_clear);
                   struct zink_framebuffer_clear_data *clear = fb_clear->clears.data;
-                  memcpy(clear + 1, clear, num_clears);
+                  memmove(clear + 1, clear, num_clears);
                   memcpy(&clear->color, &color, sizeof(color));
                } else {
                   /* no void clear needed */