ptp: ocp: upgrade serial line information

Introduce structure to hold serial port line number and the baud rate
it supports.

Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Vadim Fedorenko <vadfed@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>