ALSA: pcm: Avoid "BUG:" string for warnings again

The commit [d507941beb1e: ALSA: pcm: Correct PCM BUG error message]
made the warning prefix back to "BUG:" due to its previous wrong
prefix.  But a kernel message containing "BUG:" seems taken as an Oops
message wrongly by some brain-dead daemons, and it annoys users in the
end.  Instead of teaching daemons, change the string again to a more
reasonable one.

Fixes: 507941beb1e ('ALSA: pcm: Correct PCM BUG error message')
Cc: <stable@vger.kernel.org> # v3.19+
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/pcm_lib.c

@@ -322,7 +322,7 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
 			char name[16];
 			snd_pcm_debug_name(substream, name, sizeof(name));
 			pcm_err(substream->pcm,
-				"BUG: %s, pos = %ld, buffer size = %ld, period size = %ld\n",
+				"invalid position: %s, pos = %ld, buffer size = %ld, period size = %ld\n",
 				name, pos, runtime->buffer_size,
 				runtime->period_size);
 		}