power: qpnp-fg-gen4: Add support for weighted capacity learning

Add support to loosen capacity learning qualifying criterion.
This helps to 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: I67cf2e810649c9d77b7aeca79e235be4ab01027f
Signed-off-by: Sahil Chandna <chandna@codeaurora.org>