ALSA: ASoC: Fix at32-pcm build breakage with PM enabled

s/PDC_PTCR/ATMEL_PDC_PTCR/

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>