gnu: Remove leftover libsndfile/fixed package.

This package was equivalent to the libsndfile package, differing only in
the order of its inputs.

* gnu/packages/pulseaudio.scm (libsndfile/fixed): Remove variable.
* gnu/packages/music.scm (liquidsfz)[inputs]: Replace libsndfile/fixed with
libsndfile.
* gnu/packages/telephony.scm (mumble)[inputs]: Likewise.

gnu/packages/music.scm

@@ -4795,7 +4795,7 @@ audio samples and various soft sythesizers.  It can receive input from a MIDI ke
      `(("jack" ,jack-2)
        ("lv2" ,lv2)
        ("readline" ,readline)
-       ("libsndfile" ,libsndfile/fixed)))
+       ("libsndfile" ,libsndfile)))
     (home-page "https://github.com/swesterfeld/liquidsfz")
     (synopsis "Sampler library")
     (description "The main goal of liquidsfz is to provide an SFZ sampler

gnu/packages/pulseaudio.scm

@@ -121,14 +121,6 @@ SPARC.  Hopefully the design of the library will also make it easy to extend
 for reading and writing new sound file formats.")
     (license l:gpl2+)))
 
-;; Remove this on core-updates
-(define-public libsndfile/fixed
-  (package
-    (inherit libsndfile)
-    (inputs '())
-    (propagated-inputs
-     (list libvorbis libogg flac opus))))
-
 (define-public libsamplerate
   (package
     (name "libsamplerate")                     ; aka. Secret Rabbit Code (SRC)

gnu/packages/telephony.scm

@@ -658,7 +658,7 @@ address of one of the participants.")
     (inputs
      (list avahi
            boost
-           libsndfile/fixed
+           libsndfile
            libxi
            mesa ; avoid bundled
            openssl