i40e: Wrong truncation from u16 to u8

In this patch fixed wrong truncation method from u16 to u8 during
validation.

It was changed by changing u8 to u32 parameter in method declaration
and arguments were changed to u32.

Signed-off-by: Grzegorz Siwik <grzegorz.siwik@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
