power: supply: qg: Add support to make QG driver GKI compliant

Add support for "bms" power supply which is not present in kernel 5.4
through IIO device and properties under it through individual IIO
channels under the IIO device.

Change-Id: I55c44e5db2dc4549021cb429444c7c5afa679c3a
Signed-off-by: Shyam Kumar Thella <sthella@codeaurora.org>