backlight: qcom-spmi-wled: Convert power_supply properties to iio

Convert "bms" power_supply properties to iio channels.
Also remove the revid support and workarounds for PM8150l
V1.0 and identify the pmic type based on the driver match data.

Change-Id: I4074d33e15f7df44e628291dca25c056877ba664
Signed-off-by: Jishnu Prakash <jprakash@codeaurora.org>