[ALSA] Don't NULL check vfree argument in pdaudiocf_pcm.c

Modules: PDAudioCF driver

Don't check pointers passed to vfree for null in pdaudiocf_pcm.c

Signed-off-by: Jesper Juhl <Jesper.Juhl@Gmail.Com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>