mfd: twl6040: Add twl6040-gpio child

Add needed platform data structure and code to be able to load
the GPO child of twl6040.
Update the devicetree binding documentation at the same time.

Signed-off-by: Sergio Aguirre <[email protected]>
Signed-off-by: Peter Ujfalusi <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>
3 files changed