Merge branch 'fix/submit-and-wait-reg-sigsegv' of https://github.com/XananasX7/liburing

* 'fix/submit-and-wait-reg-sigsegv' of https://github.com/XananasX7/liburing:
  queue: fix NULL deref in _io_uring_get_cqe() for EXT_ARG_REG path