The crate targets v6.16 now, so the definitions can be removed.

Use the nightly toolchain to verify the hexagon functionality since it's
not normally built.

The vm_sockets.h header contains sockaddr_vm, which is needed
for setting up `AF_VSOCK` sockets.

Signed-off-by: John Nunley <dev@notgull.net>

* Make ioctl generation use correct version of Linux headers

Ioctls now use the same kernel version that's used in `gen/src/main.rs` for
generating other bindings. They are no longer based on any system-wide headers
which happen to exist in the system include directories.

This removes the `REISERFS_IOC_UNPACK` ioctl because reiserfs was removed from
the kernel and its userspace headers in Linux 6.13.

* Add m68k architecture support

* Generate ioctls and bindings