i40e: use pf data structure directly in i40e_ptp_rx_hang

There's no reason to pass a *vsi pointer if we already have the *pf
pointer in the only location where we call this function. Lets update
the signature and directly pass the *pf data structure pointer.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>