ALSA: pcsp - fix printk format warning again

The commit 5a641bcd 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>