Use the devm_* helpers to cleanup the probe routine. This also eliminates
having to carry the mem value in the private data for the remove.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Tested-by: Mika Westerberg <mika.westerberg@iki.fi> Acked-by: Mika Westerberg <mika.westerberg@iki.fi> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>