Always send 3 * RGBLED_NUM bytes through I2C on ps2avrGB

This wasn't going to work on boards with a different number of LEDs,
since I was always sending 48 bytes.

keyboards/ps2avrGB/ps2avrGB.c

@@ -36,7 +36,7 @@ void rgblight_set(void) {
     }
 
     i2c_init();
-    i2c_send(0xb0, (uint8_t*)led, 48);
+    i2c_send(0xb0, (uint8_t*)led, 3 * RGBLED_NUM);
 }
 
 __attribute__ ((weak))