i40e: PTP - avoid aggregate return warnings

i40e: PTP - avoid aggregate return warnings

Orabug: 23176970

Aggregate return warnings are when struct types are returned
and must be copied to the lvalue with a struct copy by the compiler.

This fixes warnings of type aggregate-return from gcc with W=2.

Change-Id: I896b1bf514544bf0faeb458869d79914b9f1b168
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit cdc3d93257e162dd12906a6e0207436c2d5c6873)
Signed-off-by: Brian Maly <brian.maly@oracle.com>