Add support for CAN FD

[0xfocu5]

From the history of issues, this library does support CAN FD, but I couldn't find any related API provided in the latest documentation. I'm not sure if it's my oversight or there is indeed no CAN FD support? Thanks!!!

[dcarr45]

Was also just looking into this, can confirm that there's no CAN FD support - the classic CAN struct is hardcoded is the only variety of frame in pkg/socketcan/frame.go.

Adding FD support shouldn't be too much of an ordeal, it's well defined in the SocketCAN docs and the struct is basically identical aside from the 64-byte rather than 8-byte data array - will definitely take some doing though. I'm not dying for FD support at the moment so I'm gonna procrastinate it but I'm interested

[adlion]

Thank you for the great package!

I am interested to have CANFD support too

[pengtech]

UP