ALSA: pcsp - fix printk format warning again

The commit 5a641bcd6398841cc4606b0a732d41a09256fd94 changed the
printk format to '%lu', but the value passed seems to be dependent
on the architecture.  On x86-64, I got a new warning now because an
int value is passed actaully.

As a workaround, just cast the value always to unsigned long.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/drivers/pcsp/pcsp_mixer.c b/sound/drivers/pcsp/pcsp_mixer.c
index 771955a..199b033 100644
--- a/sound/drivers/pcsp/pcsp_mixer.c
+++ b/sound/drivers/pcsp/pcsp_mixer.c
@@ -51,7 +51,7 @@
 	if (uinfo->value.enumerated.item > chip->max_treble)
 		uinfo->value.enumerated.item = chip->max_treble;
 	sprintf(uinfo->value.enumerated.name, "%lu",
-			PCSP_CALC_RATE(uinfo->value.enumerated.item));
+		(unsigned long)PCSP_CALC_RATE(uinfo->value.enumerated.item));
 	return 0;
 }