i40e: Remove casts of pointer to same type

Casting a pointer to a pointer of the same type is pointless,
so remove these unnecessary casts.

Done via coccinelle script:

$ cat typecast_2.cocci
@@
type T;
T *foo;
@@

-	(T *)foo
+	foo

Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>