OMAP3: pandora: enable battery backup capacitor

Pandora has a capacitor connected as backup battery, which allows
retaining RTC for some time while main battery is removed. Enable backup
battery charge function to charge that capacitor.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>