iio: mxs-lradc: add scale attribute to channels
iio: mxs-lradc: add scale attribute to channels

Some LRADC channels have fixed pre-dividers and all have an optional
divider by two which allows a maximum input voltage of VDDIO - 50mV.

This patch
 - adds the scaling info flag to all channels
 - grabs the max reference voltage per channel
   (where the fixed pre-dividers apply)
 - allows to read the scaling attribute (computed from the Vref)

Signed-off-by: Hector Palacios <a8c4a54ab41b1fd5344b908edc2fcb81d5f78d9f@digi.com>.
Signed-off-by: Alexandre Belloni <a7228e626ecf0022ac91fc1cd8db88e71d0e5e0e@free-electrons.com>
Acked-by: Marek Vasut <f40600653b33f5282fa4c5daf377dfc444fb4625@denx.de>
Signed-off-by: Jonathan Cameron <09f65b71b7655725897b2fd41a09a0cefe2e1ace@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs