gnu: QEMU: Remove obsolete patch.

* gnu/packages/virtualization.scm (qemu)[source](patches): Remove Sphinx
compatibility patch, which worked around a bug in Sphinx that has since been
fixed.
* gnu/packages/patches/qemu-sphinx-compat.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.

gnu/local.mk

@@ -1689,7 +1689,6 @@ dist_patch_DATA =						\
   %D%/packages/patches/python-waitress-fix-tests.patch		\
   %D%/packages/patches/qemu-build-info-manual.patch		\
   %D%/packages/patches/qemu-CVE-2021-20203.patch		\
-  %D%/packages/patches/qemu-sphinx-compat.patch			\
   %D%/packages/patches/qemu-glibc-2.27.patch 			\
   %D%/packages/patches/qemu-glibc-2.30.patch 			\
   %D%/packages/patches/qpdfview-qt515-compat.patch		\

gnu/packages/patches/qemu-sphinx-compat.patch

@@ -1,18 +0,0 @@
-Prevent Sphinx 4 and later from creating subdirectories, which
-the build scripts are not equipped to deal with.
-
-Taken from upstream:
-https://gitlab.com/qemu-project/qemu/-/issues/256
-https://gitlab.com/qemu-project/qemu/-/commit/269a7e97865cb863c9ca19e5f2e6a40ac9eddf82
-
-diff --git a/docs/conf.py b/docs/conf.py
---- a/docs/conf.py
-+++ b/docs/conf.py
-@@ -279,6 +279,7 @@
-      ['Stefan Hajnoczi <stefanha@redhat.com>',
-       'Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>'], 1),
- ]
-+man_make_section_directory = False
- 
- # -- Options for Texinfo output -------------------------------------------
- 

gnu/packages/virtualization.scm

@@ -159,7 +159,6 @@
         (base32
          "15iw7982g6vc4jy1l9kk1z9sl5bm1bdbwr74y7nvwjs1nffhig7f"))
        (patches (search-patches "qemu-CVE-2021-20203.patch"
-                                "qemu-sphinx-compat.patch"
                                 "qemu-build-info-manual.patch"))
        (modules '((guix build utils)))
        (snippet