In 1e5834c38a ("Refactor Linux ipc_priv header") a different
approach to passing __IPC_64 as zero was created. The tile
architecture also needs to pass __IPC_64 as zero since it does
not set CONFIG_ARCH_WANT_IPC_PARSE_VERSION in the kernel.
So create a minimal ipc_priv.h that specifies __IPC_64 as zero.
