maint: Adjust final inputs self contained check for changes.

The check script has been failing, %final-inputs have been changed
to a procedure that takes the system.

* build-aux/check-final-inputs-self-contained.scm
(final-inputs): Call %final-inputs procedure with system.

Change-Id: Id4d40387e669c996a380f64c73432d916915ead5
Signed-off-by: Rutherther <rutherther@ditigal.xyz>

build-aux/check-final-inputs-self-contained.scm

@@ -50,7 +50,7 @@
                                       directory))
                                  ((_ . directory) directory))
                                (derivation->output-paths drv)))))
-              %final-inputs))
+              (%final-inputs system)))
 
 (define (assert-valid-substitute substitute)
   "Make sure SUBSTITUTE does not refer to any bootstrap inputs, and bail out