gpio: palmas: add dt support

Add of_device_id table for Palma GPIO to be enable the
driver from DT file.

The driver can be registered from DT file as:
	palmas: tps65913@58 {
		:::::::::::
		palmas_gpio: palmas_gpio {
			compatible = "ti,palmas-gpio";
			gpio-controller;
			#gpio-cells = <2>;
		};
	};

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>