Recognize more talker IDs when parsing NMEA RMC messages

Recognize more talker IDs when parsing NMEA RMC messages

The NMEA 0183 standard says that the first two chars correspond to the
'source' of the message, right now we were only looking for 'GP' prefix
for 'GPS', but this can also be 'GL' for Glonass, 'BD' for BeiDou, 'GA'
for Galileo, or 'GN' for a generic GNSS source.

Match the RMC messages from all those variants, with this i'm able to
use my navilock nl-8002u (which uses GNRMC) as a timedelta sensor for
ntpd, and i have my GPS position in the nmea(4) sensors.

ok deraadt@