Few tests failing on ppc64le

[ignatenkobrain]

---- ringbuf_tests::test_buffer_new stdout ----
thread 'ringbuf_tests::test_buffer_new' panicked at 'assertion failed: `(left == right)`
  left: `65536`,
 right: `8192`', src/ringbuf_tests.rs:44:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
---- ringbuf_tests::test_buffer_with_cap stdout ----
thread 'ringbuf_tests::test_buffer_with_cap' panicked at 'assertion failed: `(left == right)`
  left: `65536`,
 right: `4096`', src/ringbuf_tests.rs:51:5