kselftest/alsa: pcm-test: Decrease stream duration from 4 to 2 seconds

Currently test_pcm_time() streams audio on each PCM with each
configuration for 4 seconds. This time can add up, and with the current
45 second kselftest timeout, some machines like mt8192-asurada-spherion
can't even run to completion. Lower the duration to 2 seconds to cut the
test duration in half, without reducing the test coverage.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20230620220839.2215057-3-nfraprado@collabora.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

tools/testing/selftests/alsa/pcm-test.c

@@ -258,7 +258,7 @@ static void test_pcm_time(struct pcm_data *data, enum test_class class,
 			  const char *test_name, snd_config_t *pcm_cfg)
 {
 	char name[64], key[128], msg[256];
-	const int duration_s = 4, margin_ms = 100;
+	const int duration_s = 2, margin_ms = 100;
 	const int duration_ms = duration_s * 1000;
 	const char *cs;
 	int i, err;