led: Drop FBD_FEEDBACK_LED_COLOR_LAST

With new led types we might not loop over all of them. This makes
it a bit more obvious.

src/fbd-dev-led.c

@@ -52,7 +52,7 @@ fbd_dev_led_probe_default (FbdDevLed *led, GError **error)
   gboolean success = FALSE;
 
   name = g_udev_device_get_name (priv->dev);
-  for (int i = 0; i <= FBD_FEEDBACK_LED_COLOR_LAST; i++) {
+  for (int i = 0; i <= FBD_FEEDBACK_LED_COLOR_RGB; i++) {
     g_autofree char *color = NULL;
     g_autofree char *enum_name = NULL;
     gchar *c;

src/fbd-feedback-led.h

@@ -25,7 +25,6 @@ typedef enum _FbdFeedbackLedColor {
   FBD_FEEDBACK_LED_COLOR_GREEN = 2,
   FBD_FEEDBACK_LED_COLOR_BLUE = 3,
   FBD_FEEDBACK_LED_COLOR_RGB = 4,
-  FBD_FEEDBACK_LED_COLOR_LAST = FBD_FEEDBACK_LED_COLOR_RGB,
 } FbdFeedbackLedColor;
 
 typedef struct {