power: qpnp-fg: Add snapshot of the FG driver

This is the snapshot of the fg driver as of msm-3.18 kernel
'commit d03fafd27cf9 ("qpnp-fg: fix integer overflow")'

Fix compilation errors on msm-4.9 by replacing deprecated
do_div() calls and replace spmi_dev with pdev.

Also fix checkpatch errors.

CRs-Fixed: 2246295
Change-Id: I8f946c8919321b9f0df2bc570dd191904f690dd7
Signed-off-by: Vamshi Krishna B V <vbv@codeaurora.org>