i40e: Change variable type to avoid typecheck failure

Change the variable type to avoid compiler warning about int to u16
possible data truncation.

Change-ID: I5eb3b578c86513c9625ca32d2f0b57cc01d7dc98
Signed-off-by: Kevin Scott <kevin.c.scott@intel.com>
Acked-by: Greg Rose <gregory.v.rose@intel.com>
Acked-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_common.c

@@ -1300,7 +1300,7 @@ i40e_status i40e_aq_send_driver_version(struct i40e_hw *hw,
 	struct i40e_aqc_driver_version *cmd =
 		(struct i40e_aqc_driver_version *)&desc.params.raw;
 	i40e_status status;
-	int len;
+	u16 len;
 
 	if (dv == NULL)
 		return I40E_ERR_PARAM;