doc: Change API tables to lists in the Kernel Primer.

The tables in the Kernel Primer are changed to lists. Making it easier
to update them. Other minor changes were done to ensure consitency.
The :c: and :cpp: markup has been fixed. When the documentation for a
call exists, then it is linked.

Change-Id: I8f389a0a0ca7c5fe904c0a1fa520e2e499f1001b
Signed-off-by: Rodrigo Caballero <rodrigo.caballero.abraham@intel.com>