Sascha Hauer authored Apr 09, 2013 and Alexey Mednyy committed Jan 20, 2016

The mc34708 has an improved adc. The older variants will always convert
a fixed order of channels. The mc34708 can do up to eight conversions
in arbitrary channel order. Currently this extended feature is not
supported. We only support touchscreen conversions now, which will
be sampled in a data format compatible to the older chips in order
to keep the API between the mfd and the touchscreen driver.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>