dt-bindings: tlv320adcx140: Add GPO config and drive config

Add properties for configuring the General Purpose Outputs (GPO). The
GPOs. There are 2 settings for each GPO, configuration and the output drive
type.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20200728160833.24130-1-dmurphy@ti.com


Signed-off-by: Mark Brown <broonie@kernel.org>