ALSA: pcm: 'BUG:' message unnecessarily triggers kerneloops

BugLink: http://bugs.launchpad.net/bugs/1305480

The kerneloops-daemon scans dmesg for common crash signatures, among
which is 'BUG:'. The message emitted by the PCM library is really a
warning, so the most expedient thing to do seems to be to change the
string.
Signed-off-by: NTim Gardner <tim.gardner@canonical.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/core/pcm_lib.c

@@ -345,7 +345,7 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
 			snd_pcm_debug_name(substream, name, sizeof(name));
 			xrun_log_show(substream);
 			pcm_err(substream->pcm,
-				"BUG: %s, pos = %ld, buffer size = %ld, period size = %ld\n",
+				"XRUN: %s, pos = %ld, buffer size = %ld, period size = %ld\n",
 				name, pos, runtime->buffer_size,
 				runtime->period_size);
 		}