ioq: Rewrite the spin loop to avoid a warning

With some GCC versions, --enable-ubsan leads to this warning:

    src/ioq.c: In function ‘ioq_slot_wait’:
    src/ioq.c:287:17: warning: ignoring loop annotation
      287 |                 for (int j = 0; j < (1 << i); ++j) {
          |                 ^~~

presumably due to UBSan rewriting the shift to check for overflow.  Work
around this by precomputing the iteration count.

0 files changed, 0 insertions, 0 deletions