net: Convert PHYs hwtstamp callback to use kernel_hwtstamp_config

The PHYs hwtstamp callback are still getting the timestamp config from
ifreq and using copy_from/to_user.
Get rid of these functions by using timestamp configuration in parameter.
This also allow to move on to kernel_hwtstamp_config and be similar to
net devices using the new ndo_hwstamp_get/set.

This adds the possibility to manipulate the timestamp configuration
from the kernel which was not possible with the copy_from/to_user.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>