Minor issue (typo)

Hi,

I was glancing over your code and found a minor error:

```
	if( ( irqRegs & IRQ_RX_TX_TIMEOUT ) == IRQ_RX_TX_TIMEOUT ) {
		if (OperatingMode == MODE_TX) {
			HalPostTx();

			if (txTimeout)
				txTimeout();
		} else if (OperatingMode == MODE_TX) {
			HalPostRx();

			if (rxTimeout)
				rxTimeout();
		}
	}
```

I believe the 2nd MODE_TX should be MODE_RX.

Cheers,
Juergen
