net/ixgbe/base: enable LASI only for X552 devices

net/ixgbe/base: enable LASI only for X552 devices

Enable the Link Alarm Status Interrupt (LASI) only for X552 devices
to receive notifications of the link configurations of the external
PHY and correspondingly support the configuration of the internal
iXFI link, since iXFI does not support auto-negotiation.

This is not required for X553 devices having KR support, which
performs auto-negotiations and which is used as the internal
link to the external PHY.

Signed-off-by: Wei Dai <wei.dai@intel.com>