power: qpnp-qg: Update the recharge/hold-SOC logic

In the current code the hold-soc logic scales the SOC
when there is a discharge or a re-charge event. However,
the expectation is to hold the SOC to 100% until we
recharge back to 100%. Only start scaling the SOC
if we are indeed discharging (msoc < recharge_soc)
or USB is removed. Also, scale the SOC slower if
we are in the maintenance mode.

Also, the expectation of recharge SOC is to start
start recharge at that SOC value and not a point lower,
fix it accordingly.

Change-Id: Ifb21caf0531fdf042d46a8fd906cb4e067e9910f
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>