power-supply: Add charging and fuel gauging drivers

Add PMIC charging and fuel gauge drivers on msm-3.18.

This snapshot is taken as of msm-3.14 commit 3bc54cf86b (Merge "msm:
camera: Add dummy sub module in sensor pipeline")

Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>