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

This reverts commit a88b1672.

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>

scripts/kernel-doc

@@ -1849,9 +1849,6 @@ sub output_function_rst(%) {
 	$count++;
 	$type = $args{'parametertypes'}{$parameter};
 
-	# RST doesn't like address_space tags at function prototypes
-	$type =~ s/__(user|kernel|iomem|percpu|pmem|rcu)\s*//;
-
 	if ($type =~ m/([^\(]*\(\*)\s*\)\s*\(([^\)]*)\)/) {
 	    # pointer-to-function
 	    print $1 . $parameter . ") (" . $2;