TransceiverUHD: Add receive overpower alerting
TransceiverUHD: Add receive overpower alerting

Detect when the sample input level reaches 94% of full scale input,
which equates to amplitude of 120 for 8-bit samples post-conversion,
and log the event with ALERT level.

Signed-off-by: Tom Tsou <96835dd8bfa718bd6447ccc87af89ae1675daeca@tsou.cc>

flyhawk007/OpenBTS-UMTS,flyhawk007/OpenBTS-UMTS,RangeNetworks/OpenBTS-UMTS,flyhawk007/OpenBTS-UMTS,RangeNetworks/OpenBTS-UMTS,flyhawk007/OpenBTS-UMTS,RangeNetworks/OpenBTS-UMTS,RangeNetworks/OpenBTS-UMTS