full RGB support for users of tradfri GW (#9411)

* Update tradfri.py

## 201709013: set_hex_color() seems not to work in pytradfri api - set_rgb_color() does 
## -> changed function set_hex_color() to set_rgb_color() 
## tested w. IKEA tradfri GW and zigbee rgb PWM module (dresden elektronik FLS-PP lp)

* Update tradfri.py

Setup: 
Home Assistant 0.53.0
pytradfri 2.2 
IKEA tradfri gateway fw 1.1.0015
zigbee rgb PWM module (dresden elektronik FLS-PP lp) 

Issue: 
pytradfri's set_hex_color() does not work for arbitrary colors with the current IKEA tradfri gateway. Only setting rgb hex values (param 5706) of some predefined colors has the desired effect. Others will fall back to one predefined value. I assume, the GW doesn't allow for values deviating from the predefined values. 

However, pytradfri's set_rgb_color() does also work for arbitrary colors. Latest pytradfri (2.2/PR51?) will convert rgb to xy and send xy thru the GW (param 5709 and 5710). 

 -> changed the function used from set_hex_color() to set_rgb_color() in HA's component\light\tradfri

Result: 
Full RGB support with arbitrary colors with my setup. 

Unfortunately I cannot test tradfri GW with other bulbs (no have hue/lightify bulbs). 
___ 

Predefined colors from <https://github.com/ggravlingen/pytradfri/pull/51>: 
 this.f3891b = new HashMap();
        this.f3891b.put("f5faf6", new C1386c(0.3804d, 0.3804d, "f5faf6", 0.54d));
        this.f3891b.put("f1e0b5", new C1386c(0.4599d, 0.4106d, "CCT_LIGHT_NEUTRAL", 0.61d));
        this.f3891b.put("efd275", new C1386c(0.5056d, 0.4152d, "efd275", 0.66d));
        this.f3891b.put("dcf0f8", new C1386c(0.3221d, 0.3317d, "dcf0f8", 0.45d));
        this.f3891b.put("eaf6fb", new C1386c(0.3451d, 0.3451d, "eaf6fb", 0.48d));
        this.f3891b.put("f5faf6", new C1386c(0.3804d, 0.3804d, "f5faf6", 0.54d));
        this.f3891b.put("f2eccf", new C1386c(0.4369d, 0.4041d, "f2eccf", 0.59d));
        this.f3891b.put("CCT_LIGHT_NEUTRAL", new C1386c(0.4599d, 0.4106d, "CCT_LIGHT_NEUTRAL", 0.61d));
        this.f3891b.put("efd275", new C1386c(0.5056d, 0.4152d, "efd275", 0.66d));
        this.f3891b.put("ebb63e", new C1386c(0.5516d, 0.4075d, "ebb63e", 0.68d));
        this.f3891b.put("e78834", new C1386c(0.58d, 0.38d, "e78834", 0.69d));
        this.f3891b.put("e57345", new C1386c(0.58d, 0.35d, "e57345", 0.67d));
        this.f3891b.put("da5d41", new C1386c(0.62d, 0.34d, "da5d41", 0.7d));
        this.f3891b.put("dc4b31", new C1386c(0.66d, 0.32d, "dc4b31", 0.73d));
        this.f3891b.put("e491af", new C1386c(0.5d, 0.28d, "e491af", 0.57d));
        this.f3891b.put("e8bedd", new C1386c(0.45d, 0.28d, "e8bedd", 0.53d));
        this.f3891b.put("d9337c", new C1386c(0.5d, 0.24d, "d9337c", 0.55d));
        this.f3891b.put("c984bb", new C1386c(0.34d, 0.19d, "c984bb", 0.38d));
        this.f3891b.put("8f2686", new C1386c(0.31d, 0.12d, "8f2686", 0.33d));
        this.f3891b.put("4a418a", new C1386c(0.17d, 0.05d, "4a418a", 0.18d));
        this.f3891b.put("6c83ba", new C1386c(0.2d, 0.1d, "6c83ba", 0.22d));
        this.f3891b.put("a9d62b", new C1386c(0.4099999964237213d, 0.5099999904632568d, "a9d62b", 0.654d));
        this.f3891b.put("d6e44b", new C1386c(0.44999998807907104d, 0.4699999988079071d, "d6e44b", 0.65d));

homeassistant/components/light/tradfri.py

@@ -179,8 +179,8 @@ class Tradfri(Light):
             self._api(self._light_control.set_state(True))
 
         if ATTR_RGB_COLOR in kwargs and self._light_data.hex_color is not None:
-            self._api(self._light.light_control.set_hex_color(
-                color_util.color_rgb_to_hex(*kwargs[ATTR_RGB_COLOR])))
+            self._api(self._light.light_control.set_rgb_color(
+                *kwargs[ATTR_RGB_COLOR]))
 
         elif ATTR_COLOR_TEMP in kwargs and \
                 self._light_data.hex_color is not None and self._ok_temps: