of_batterydata: add functions to support SOH based profile loading

Add helper functions of_batterydata_get_aged_profile_count() and
of_batterydata_read_soh_aged_profiles() to support SOH based
profile loading. Since this requires SOH ranges to be parsed from
multiple profiles for the same battery, add a data structure
soh_range that can be populated for the number of available
battery profiles.

Change-Id: I9b17d1311fb158b59fa5b17390f3b1a29b76b0e9
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>