MIPS: au1xxx-ide: Fix build with CONFIG_PM

au1xxx_power_dev_t? is never defined;  get rid of all PM stuff as well
since it is not in the driver source anyway.

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>