use any /dev/gnssX if sys/class/gnss/gnssX/type shows something known

Most things in /dev are automatically used if it is clear what it is, so why not doing that regarding gnss? Or at least as a fallback.

Currently as a type in sysfs there is: NMEA, SiRF, UBX, MTK

So depending on type there could be just nmea passthrough or some more sophisticated agps stuff.