ARM: OMAP3+ ABB: allow ABB vset efuse override support

On certain silicon like OMAP5, ABB voltage values are now
encoded in efuse itself. So strip out the data and push
into the LDO as needed.

Change-Id: Ie5f21aa704248f1166fb07891bf30b4fe837a6a8
Signed-off-by: Nishanth Menon <nm@ti.com>