i40e: Extract detection of HW flags into a function

Move code detecting HW flags based on device type and FW API version
into a single function.

Signed-off-by: Piotr Azarewicz <piotr.azarewicz@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>