Add ability to set LED colors in DBus

phosphor-led-sysfs parses sysfs LED node names
in the form of "devicename:colour:function" as
described in

https://github.com/torvalds/linux/blob/master/Documentation/leds/leds-class.txt#L46

and then converts the "colour" part into the proper
value of the DBus 'Color' property using the
xyz.openbmc_project.Led.Physical.Palette interface.

In order for the led nodes to have their Color set,
the corresponding led nodes in devicetree must have
correct 'label' properties, e.g.:

leds {
    compatible = "gpio-leds";

    heartbeat {
        label = "bmc:green:hearbeat";
        gpios = <&gpio ASPEED_GPIO(R, 4) GPIO_ACTIVE_LOW>;
    };
    power_red {
        label = "system:red:power";
        gpios = <&gpio ASPEED_GPIO(N, 1) GPIO_ACTIVE_LOW>;
    };
}

Change-Id: I094f0e434bdd262995752576a3c792ccd5dbb3e2
Signed-off-by: Alexander Soldatov <a.soldatov@yadro.com>
Signed-off-by: Alexander Amelkin <a.amelkin@yadro.com>
3 files changed