Now that several arch documents were converted to ReST,
add their indexes to Documentation/index.rst and remove the
:orphan: from them.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Rename the xtensa documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>