ptp: add the pin GET/SETFUNC ioctls to the testptp program.

This patch adds a option to the test program that lists the
programmable pins on a PTP Hardware Clock device, assuming there
are any such pins. A second option lets the user reprogram the
auxiliary function of a single pin.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>