Documentation: coresight: convert txt to rst

Documentation: coresight: convert txt to rst

This changes from plain text to reStructuredText as suggestion
in doc-guide [1]

[1] https://www.kernel.org/doc/html/latest/doc-guide/sphinx.html

Some adaptations such as: literal block, ``inline literal`` and
alignment text,...

Signed-off-by: Phong Tran <tranmanphong@gmail.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>