leds: qpnp-flash-v2: Convert power_supply properties to iio

Convert "main_psy" and "bms" power_supply properties to iio
channels. Also remove the revid support and identify the
pmic type based on the driver match data.

Change-Id: I70910fc502cfb1e4cd7906eca234e3a44d2f9c84
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>