zink: pass nr_cbufs to vkCmdSetColorWriteEnableEXT
VUID-vkCmdDrawMultiEXT-attachmentCount-06667 specifies that attachmentCount needs to match the attachment count from the blend-state, but we're setting it to maxColorAttachments.
VUID-vkCmdDrawMultiEXT-attachmentCount-06667 specifies that attachmentCount needs to match the attachment count from the blend-state, but we're setting it to maxColorAttachments.