Fix some style issues in sysdeps/nacl/irt_syscalls.*

- Untabify code
- Add line breaks for >80 lines
- Fix the type __nacl_irt_thread_create

BUG=https://code.google.com/p/chromium/issues/detail?id=352498
R=mseaborn@chromium.org

Review URL: https://codereview.chromium.org/200463002
2 files changed