Handle OEM7 RXSTATUS logs

[pjreed]

I discovered recently that a number of the flags in the RXSTATUS bit field have changed significantly between OEM6 and OEM7.

For reference, OEM6: https://www.novatel.com/assets/Documents/Manuals/om-20000129.pdf
And OEM7: https://docs.novatel.com/OEM7/Content/Logs/RXSTATUS.htm

The driver was originally designed to work with OEM6 devices, and it may print incorrect information in messages and diagnostics on OEM7 devices.