icE1usb fw/gpsdo: Attempt to recover from bad tuning

If we're in hold over mode and getting a bunch of invalid
frequency measurement despite a good fix, then we most likely
ended up on a bad tuning value and we need to recover by starting
from scratch.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Change-Id: If8503a3eaf695e02a0ef0a3b6536de985d247c20
1 file changed