Remove irrevelant 9539 mention in title

README.md

@@ -1,4 +1,4 @@
-# USB-I2C bridge (ATmega8U2 + TCA9539)
+# USB-I2C bridge (ATmega8U2)
 
 USB CDC-ACM (virtual COM port) to I2C master. No LUFA, no interrupts: ~2.5 KB flash.