tps6105x: add optional devicetree support

tps6105x: add optional devicetree support

This driver currently requires platform data to specify the
operational mode and regulator init data (in case of regulator
mode).

Optionally specify the operational mode by looking at the name
of the devicetree child node.

Example: put chip in regulator mode:

i2c0 {
	tps61052@33 {
		compatible = "ti,tps61052";
		reg = <0x33>;

		regulator {
                            regulator-min-microvolt = <5000000>;
                            regulator-max-microvolt = <5000000>;
                            regulator-always-on;
		};
	};
};

Tree: linux-next
Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
Link: https://lore.kernel.org/r/20191119154611.29625-2-TheSven73@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>