[ALSA] ARM AACI primecell driver

ARM,/arm/Makefile,ARM AACI PL041 driver
Add support for the ARM AACI Primecell, which provides an AC'97
based interface.  This driver only provides playback support.

This has been extensively tested with an LM4549 AC'97 codec.

Signed-off-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>