ARM: defconfig: update U8500 defconfig

Some config options like perf events and PM are now implicit,
we have an upstream driver for the AK8974, and we really
want the HRTIMER software triggers from configfs with some
of the sensors.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>