Fix TSIP Satellite Check

[ve7fet]

In voter.c, process_gps:

if (gps_buf[1] == 0xac) // AC is the Supplemental Timing Packet
{

...

gps_nsat = 3; // Hah, we're faking the number of received sats.

if ((gps_state == GPS_STATE_RECEIVED) && (gps_nsat > 0) && gps_time)
{

Investigate why we're manually setting the number of satellites in view, and see if we can do an actual check from the TSIP string to validate instead.

[ve7fet]

Looks like TSIP timing packets AB and AC do not actually report number of satellites in view, so that would be why it is manually set.

Will add a note to the source.