hasvk: Mark VK_IMAGE_LAYOUT_ATTACHMENT_OPTIMAL as stencil write optimal

hasvk: Mark VK_IMAGE_LAYOUT_ATTACHMENT_OPTIMAL as stencil write optimal

VK_KHR_synchronization2 added VK_IMAGE_LAYOUT_ATTACHMENT_OPTIMAL, which
was not previously recognized by vk_image_layout_stencil_write_optimal.

Would close https://gitlab.freedesktop.org/mesa/mesa/-/issues/5578 if it
wasn't already closed.

Fixes: b996fa8efaa ("anv: implement VK_KHR_synchronization2")

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19876>