ptp: remove 32 bit get/set methods.

All of the PHC drivers have been converted to the new methods.  This patch
converts the three remaining callers within the core code and removes the
older methods for good.  As a result, the core PHC code is ready for the
year 2038.  However, some of the PHC drivers are not quite ready yet.

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