bcachefs: Etyzinger cleanups

Pull out eytzinger.c and kill eytzinger_cmp_fn. We now provide
eytzinger0_sort and eytzinger0_sort_r, which use the standard cmp_func_t
and cmp_r_func_t callbacks.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
7 files changed