igc: Do not enable crosstimestamping for i225-V models

It was reported that when PCIe PTM is enabled, some lockups could
be observed with some integrated i225-V models.

While the issue is investigated, we can disable crosstimestamp for
those models and see no loss of functionality, because those models
don't have any support for time synchronization.

Fixes: a90ec848

 ("igc: Add support for PTP getcrosststamp()")
Link: https://lore.kernel.org/all/924175a188159f4e03bd69908a91e606b574139b.camel@gmx.de/
Reported-by: Stefan Dietrich <roots@gmx.de>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Nechama Kraus <nechamax.kraus@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>