docs: Makefile: store __pycache__ at the output directory

Instead of blocking creation of *.pyc cache, store python
cache under Documentation/output/__pycache__

Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
Message-ID: <1b9e7f34c1d99a27a8abb308da3221b4663b5693.1745539360.git.mchehab+huawei@kernel.org>

Author: mchehab

Documentation/Makefile

@@ -84,7 +84,7 @@ loop_cmd = $(echo-cmd) $(cmd_$(1)) || exit;
 
 quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)
       cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/userspace-api/media $2 && \
-	PYTHONDONTWRITEBYTECODE=1 \
+	PYTHONPYCACHEPREFIX=$(abspath $(BUILDDIR)/__pycache__) \
 	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(src)/$5/$(SPHINX_CONF)) \
 	$(PYTHON3) $(srctree)/scripts/jobserver-exec \
 	$(CONFIG_SHELL) $(srctree)/Documentation/sphinx/parallel-wrapper.sh \