i40e: fix incorrect function documentation comment

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

drivers/net/ethernet/intel/i40e/i40e_ptp.c

@@ -140,8 +140,7 @@ static int i40e_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
  * @ptp: The PTP clock structure
  * @delta: Offset in nanoseconds to adjust the PHC time by
  *
- * Adjust the frequency of the PHC by the indicated parts per billion from the
- * base frequency.
+ * Adjust the current clock time by a delta specified in nanoseconds.
  **/
 static int i40e_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 {