[ALSA] make the pxa2xx-ac97 module more robust against PXA27x bugs

Modules: ARM PXA2XX driver

The SDONE and CDONE interrupt on the PXA27x might become unusable in
some conditions.  Let's use an hybrid approach (interrupt with timeout)
to have the best possible behavior in all conditions.

Also let's not care about CAR_CAIP anymore.  This is useless.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>