apm_power: support using VOLTAGE_* properties for apm calculations
apm_power: support using VOLTAGE_* properties for apm calculations

It's pretty dummy, but useful for batteries for which we can only
get voltages.

Signed-off-by: Dmitry Baryshkov <b6edad08270b2e4ffbcb0879e25a0e29a48c5275@gmail.com>
Signed-off-by: Anton Vorontsov <3d4412bea4b4b5bb6ad28995d4e9c3e958df972b@mail.ru>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs