power: qpnp-fg-gen3: Get the raw MSOC directly from FG register

Use the MSOC raw value directly from the register instead of
extrapolating it from MSOC value to avoid any rounding-off
errors.

CRs-Fixed: 2080211
Change-Id: I91d98c6aa8a63344ff79b5414c45d0f5a5b52b81
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>