power: qcom: Add snapshot of charger and fuel gauge drivers

This is a snapshot of the charger and fuel gauge drivers as of msm-4.9
commit 'fc9ce0e0a100 ("Merge changes  into msm-4.9")'.

Updated source in battery.c and qpnp-qnovo.c as struct 'class' member
'class_attrs' is deprecated.

Changed the way of struct extcon access from direct access to all via
APIs in smb138x-charger.c.

This change also includes some fixups for trivial checkpatch warnings.

Change-Id: I2b597dc208d6e9a7b1b265e0907958aa2208231a
Signed-off-by: Harry Yang <harryy@codeaurora.org>