gnu: mpv: Fix build by using pkg-config for smbclient.

This is a followup to commit 710964d.

* gnu/packages/video.scm (mpv)[arguments]: Remove 'patch-wscript' phase.

gnu/packages/video.scm

@@ -755,14 +755,7 @@ (define-public mpv
           'configure 'setup-waf
           (lambda* (#:key inputs #:allow-other-keys)
             (copy-file (assoc-ref inputs "waf") "waf")
-            (setenv "CC" "gcc")))
-         (add-before
-          'configure 'patch-wscript
-          (lambda* (#:key inputs #:allow-other-keys)
-            (substitute* "wscript"
-              ;; XXX Remove this when our Samba package provides a .pc file.
-              (("check_pkg_config\\('smbclient'\\)")
-               "check_cc(lib='smbclient')")))))
+            (setenv "CC" "gcc"))))
        ;; No check function defined.
        #:tests? #f))
     (home-page "http://mpv.io/")