docs: pcmcia: convert docs to ReST and rename to *.rst

Convert the pcmcia docs to ReST format. Most of the changes here
are trivial.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

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>
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>