power: qcom: Add the QPNP QGAUGE (QG) driver

The QG driver adds support for battery gauging and reporting
the battery specific parameters to userspace. The driver comprises
of the below files:

qpnp-qg.c: Core QG driver
qg-soc.c: SOC (state of charge) scaling operations
qg-util.c: Common functions
qg-battery-profile.c: Parsing battery profile from DT
qg-profile-lib.c: Operations on battery profiles
qg-sdam.c: SDAM interface for QG

This commit also adds the below UAPI files,

qg.h: QG data shared between kernel and userspace QG modules
qg-profile.c: Profile data exchange between kernel and userspace.

CRs-Fixed: 2190528
Change-Id: I97f9d051692ed659030136a622e62009da55b462
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>