net/mlx5e: IPoIB, Add PTP ioctl support for child interface

Add support to control precision time protocol on child interfaces
using ioctl.

This commit changes the following:
- Change parent ioctl function to be non static
- Reuse the parent ioctl function in child devices

Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>