[ARM] 5084/1: zylonite: Register AC97 device

The Zylonite has an AC97 subsystem on it so register the AC97 controller
device.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>