i40e: trivial: drop duplicate definition

The probe routine already had a u32 val declared, no need
to do it again.  Found by W=2 compile.

Change-ID: Id7b65f6d0ef6bb71067d0557f5be0202b6d8741e
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>