i40e: Remove unnecessary aer.h include

<linux/aer.h> is unused, so remove it.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>