Refactor: use the cache_bin_sz_t typedef instead of direct uint16_t

any future changes to the underlying data type for bin sizes
(such as upgrading from `uint16_t` to `uint32_t`) can be achieved
by modifying only the `cache_bin_sz_t` definition.

Signed-off-by: Xin Yang <yangxin.dev@bytedance.com>
2 files changed