pm2301-charger: Always compile the PM2301 Charger driver with AB8500 Battery Mgnt

The PM2301 Charger should always be available when using the AB8500
Battery Management system, we're ensuring this will be the case.

Signed-off-by: Marcus Cooper <marcus.xm.cooper@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Hakan BERG <hakan.berg@stericsson.com>
Reviewed-by: Mian Yousaf KAUKAB <mian.yousaf.kaukab@stericsson.com>