Using readl, writel, etc. resulted in some architectures, such as
s390, expanding the member names into zpci_writel.  Obviously not the
intended result.

Fixes s390 build breakage introduced by "40830813 - ALSA: hda - Allow
different ops to read/write registers"
Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>