avdevice/alsa: fix indefinite stop on closing PCM capture

Fixes: https://bugs.archlinux.org/task/58619

Found-by: Elias (Bleuzen) https://bugs.archlinux.org/user/26956
Signed-off-by: Nicolas George <george@nsup.org>

libavdevice/alsa.c

@@ -300,8 +300,10 @@ av_cold int ff_alsa_close(AVFormatContext *s1)
 {
     AlsaData *s = s1->priv_data;
 
-    snd_pcm_nonblock(s->h, 0);
-    snd_pcm_drain(s->h);
+    if (snd_pcm_stream(s->h) == SND_PCM_STREAM_PLAYBACK) {
+        snd_pcm_nonblock(s->h, 0);
+        snd_pcm_drain(s->h);
+    }
     av_freep(&s->reorder_buf);
     if (CONFIG_ALSA_INDEV)
         ff_timefilter_destroy(s->timefilter);