[light] Use reciprocal multiply in normalize_color

Replace 3 software float divides (__divsf3) with 1 divide + 3 native
mul.s instructions. Xtensa has no FPU divide, so __divsf3 is a ~20-30
cycle software routine. This saves ~40-60 cycles per normalize_color
call for +8 bytes of flash.

esphome/components/light/light_color_values.h

@@ -104,9 +104,10 @@ class LightColorValues {
         this->green_ = 1.0f;
         this->blue_ = 1.0f;
       } else {
-        this->red_ /= max_value;
-        this->green_ /= max_value;
-        this->blue_ /= max_value;
+        float inv = 1.0f / max_value;
+        this->red_ *= inv;
+        this->green_ *= inv;
+        this->blue_ *= inv;
       }
     }
   }