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

The converted files are focused at the Kernel internal API,
so, this is a good candidate for the kernel API set of books.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/serial/README.cycladesZ → Documentation/serial/cyclades_z.rst

@@ -1,8 +1,11 @@
+================
+Cyclades-Z notes
+================
 
 The Cyclades-Z must have firmware loaded onto the card before it will
 operate.  This operation should be performed during system startup,
 
 The firmware, loader program and the latest device driver code are
 available from Cyclades at
-    ftp://ftp.cyclades.com/pub/cyclades/cyclades-z/linux/
 
+    ftp://ftp.cyclades.com/pub/cyclades/cyclades-z/linux/