add backlight support (probably)

keyboards/xd75/config.h

@@ -49,9 +49,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* COL2ROW, ROW2COL, or CUSTOM_MATRIX */
 #define DIODE_DIRECTION COL2ROW
  
-// #define BACKLIGHT_PIN B7
-// #define BACKLIGHT_BREATHING
-// #define BACKLIGHT_LEVELS 3
+#define BACKLIGHT_PIN F5
+#define BACKLIGHT_BREATHING
+#define BACKLIGHT_LEVELS 3
 
 
 /* Debounce reduces chatter (unintended double-presses) - set 0 if debouncing is not needed */