radv: fix setting the number of rectangles when it's dyanmic
We need to know the number of rectangles. This fixes new CTS dEQP-VK.draw.discard_rectangles.dynamic_*. Fixes: 5db0bf99 ("radv: Implement VK_EXT_discard_rectangles.") Signed-off-by:Samuel Pitoiset <samuel.pitoiset@gmail.com> Reviewed-by:
Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>