doc-rst: Revert "kernel-doc: fix handling of address_space tags"

doc-rst: Revert "kernel-doc: fix handling of address_space tags"

This reverts commit 6149fc12c074718102f74762117822ab10047322.

From the origin comit log::

  The RST cpp:function handler is very pedantic: it doesn't allow any
  macros like __user on it

Since the kernel-doc parser does NOT make use of the cpp:domain, there
is no need to change the kernel-doc parser eleminating the address_space
tags.

Signed-off-by: Markus Heiser <markus.heiser@darmarIT.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>