icE1usb fw: Turn green LED off completely if no E1 signal is received

We don't really have an idea of the analog signal level and hence
no true LOS detection.  However, we can check the Rx clock tick counter
to detect if there is at least still any kind of signal at all or not.

Change-Id: Ibd23cbf1d044b46d8fed48fb97622e6ef980b99f
2 files changed