regulator: Move VCOINCELL to be the last element of mc13892_regulators array

In include/linux/mfd/mc13892.h, we define MC13892_VCOINCELL as 23.
Thus VCOINCELL should be defined as 23th element in mc13892_regulators array, not the first one.
This actually fixes an off-by-one bug while accessing mc13892_regulators array.

For example,
In mc13892_regulator_probe, we use MC13892_VCAM as array index of mc13892_regulators array.
        mc13892_regulators[MC13892_VCAM].desc.ops->set_mode
                = mc13892_vcam_set_mode;
Currently, it access mc13892_regulators[12] ,which is VAUDIO not VCAM.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>