turnip: Demote API version to 1.1.
We don't support major 1.2 required extensions like timeline semaphores. Fixes many complaints in the dEQP-VK.info.vulkan1p2.* group.
We were originally bumped to 1.2 in 75755e0e ("turnip: Pretend to support Vulkan 1.2") but hopefully that build issue has been fixed in the entrypoint reworks since then.