gpio: davinci: Use dev name for label and automatic base selection

Use dev_name to get a unique label and use -1 for a base to get our
selection automatically. We pull in all GPIOs per chip now so this
does not have the effect of out of order labels like before.

We do these both together so we can drop all the static data in one
patch. This also lets us normalize the return paths as we don't need
any cleanup after this change.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>