pulse: fix negative PA_ERR_NODATA comparison in pulse_delay

[GitHub pull_request - opened <github@alsa-project.org>]

alsa-project/alsa-plugins pull request #68 was opened from dirty49374:

When `pa_stream_get_latency()` returns `-PA_ERR_NODATA`, `pulse_delay()` compares it against the positive `PA_ERR_NODATA` constant and returns `-EIO`. This turns temporarily unavailable latency information into an I/O error for ALSA clients.

Compare against `-PA_ERR_NODATA` so this case follows the existing mainloop wait/retry path. Other errors still return `-EIO`.

Validation:
- Built the PulseAudio plugins with `make -C pulse -j4`.
- A local test harness exercising the actual `pulse_delay()` implementation passed success, temporary NODATA/retry, permanent error, retry followed by permanent error, and connection failure cases. The NODATA regression case fails with the original comparison. The harness is not included in this one-line patch.
- In a 20-second local CPAL/ALSA integration probe, injecting `-PA_ERR_NODATA` during capture and playback produced I/O errors with the original plugin; the source-built patched plugin continued with zero reported stream errors.

Request URL   : https://github.com/alsa-project/alsa-plugins/pull/68
Patch URL     : https://github.com/alsa-project/alsa-plugins/pull/68.patch
Repository URL: https://github.com/alsa-project/alsa-plugins