power: fg-alg: Loosen capacity learning qualification criterion

Learn capacity from any starting battery SOC to any ending battery
SOC, provided, battery SOC changes by at least 10 % during charging.
Assign weight to this capacity learning event based on the change in
battery SOC.

Change-Id: I5c5ce515cbe0c76b1ff845432e8ed32e2f5c342d
Signed-off-by: Sahil Chandna <chandna@codeaurora.org>