power: qpnp-qg: Add handling for SYS_SOC

Use the raw SYS_SOC to calculate the MSOC. Adjust
the SOC at cutoff and termination for better user
experience.

Change-Id: I1d1a0eb19cb89df754a9694c1484de37db2eb218
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>