Add support for the TPS65086 PMIC GPOs.

TPS65086 has four configurable GPOs that can be used for several
purposes. These are output only.
Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>