docs: prevent warnings due to autosectionlabel

Changeset 58ad30cf91f0 ("docs: fix reference to core-api/namespaces.rst")
enabled a new feature at Sphinx: it will now generate index for each
document title, plus to each chapter inside it.

There's a drawback, though: one document cannot have two sections
with the same name anymore.

A followup patch will change the logic of autosectionlabel to
avoid most creating references for every single section title,
but still we need to be able to reference the chapters inside
a document.

There are a few places where there are two chapters with the
same name. This patch renames one of the chapters, in order to
avoid symbol conflict within the same document.

PS.: as I don't speach Chinese, I had some help from a friend
(Wen Liu) at the Chinese translation for "publishing patches"
for this document:

Documentation/translations/zh_CN/process/5.Posting.rst

Fixes: 58ad30cf91f0 ("docs: fix reference to core-api/namespaces.rst")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/2bffb91e4a63d41bf5fae1c23e1e8b3bba0b8806.1584716446.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: index.rst: don't use genindex for pdf output

The genindex logic is meant to be used only for html output, as
pdf build has its own way to generate indexes.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Vinod Koul <vkoul@kernel.org> # dmaengine and soundwire
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

dmaengine: doc: ReSTize pxa_dma doc

This converts and moves pxa_dma file with some format
changes for RST style

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

dmaengine: doc: ReSTize dmatest doc

This converts and moves dmatest file with some format
changes for RST style

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

dmaengine: doc: ReSTize client API doc

This converts and moves client API file with some format
changes for RST style

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

dmaengine: doc: ReSTize provider doc

This moves and converts provider file with some format changes
for RST style

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

dmaengine: doc: Add ReST style dmaengine document

This removes the index file and adds the index.rst as placeholder
and update driver-api index to add dmaengine. As a consequence
dmaengine documentation will be in driver-api/

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>