ALSA: cs553*: Fix dependencies

The CS5530, CS5535 and CS5536 chipsets are companions of the Geode
series of processors, which are 32-bit x86 processors. So the
snd-cs5530 and snd-cs5535audio drivers are only needed on this
architecture, except for build testing purpose.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>