Fix apparent typo in WhiteFox LED config

It seems the led_mask is set incorrectly on the WhiteFox meaning that
the LED at C9-1 (the space bar) doesn't get lit.  I can't see any reason
for this to be intentional so I am pretty sure it's a typo.  At the very
least it fixes the space bar LED for me.

keyboards/whitefox/board_is31fl3731c.h

@@ -31,7 +31,7 @@ static const uint8_t led_mask[] = {
 	0xFF, 0x00, /* C6-1 -> C6-16 */
 	0xFF, 0x00, /* C7-1 -> C7-16 */
 	0xFF, 0x00, /* C8-1 -> C8-16 */
-	0xFE, 0x00, /* C9-1 -> C9-16 */
+	0xFF, 0x00, /* C9-1 -> C9-16 */
 };
 
 // The address of the LED