- add a product parameter to the function prototype
This would be too invasive. Are you using the telit gprs-context driver?
If so, you'd be better off changing that one to accept a custom data
structure instead of a GAtChat. See drivers/hfpmodem for an example. Or
write a custom driver for your needs...
- change the vendor parameter with a structure of two variables
This is probably the most suitable solution for me.