kernel-doc: Handle returning pointers to pointers

Clearly nobody ever tried to build the documentation for the radix tree
before:

include/linux/radix-tree.h:400: warning: cannot understand function
prototype: 'void ** radix_tree_iter_init(struct radix_tree_iter *iter,
unsigned long start) '

Indeed, the regexes only handled a single '*', not one-or-more.  I have
tried to fix that, but now I have perl regexes all over my hands, and
I fear I shall never be clean again.
Signed-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

scripts/kernel-doc

@@ -2582,21 +2582,21 @@ sub dump_function($$) {
         $noret = 1;
     } elsif ($prototype =~ m/^()([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
 	$prototype =~ m/^(\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
-	$prototype =~ m/^(\w+\s*\*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
+	$prototype =~ m/^(\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
 	$prototype =~ m/^(\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
 	$prototype =~ m/^(\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
 	$prototype =~ m/^(\w+\s+\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
-	$prototype =~ m/^(\w+\s+\w+\s+\w+\s*\*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
+	$prototype =~ m/^(\w+\s+\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\(]*)\)/ ||
 	$prototype =~ m/^()([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
 	$prototype =~ m/^(\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
-	$prototype =~ m/^(\w+\s*\*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
+	$prototype =~ m/^(\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
 	$prototype =~ m/^(\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
-	$prototype =~ m/^(\w+\s+\w+\s*\*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
+	$prototype =~ m/^(\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
 	$prototype =~ m/^(\w+\s+\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
-	$prototype =~ m/^(\w+\s+\w+\s+\w+\s*\*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
+	$prototype =~ m/^(\w+\s+\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
 	$prototype =~ m/^(\w+\s+\w+\s+\w+\s+\w+)\s+([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
-	$prototype =~ m/^(\w+\s+\w+\s+\w+\s+\w+\s*\*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
-	$prototype =~ m/^(\w+\s+\w+\s*\*\s*\w+\s*\*\s*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/)  {
+	$prototype =~ m/^(\w+\s+\w+\s+\w+\s+\w+\s*\*+)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/ ||
+	$prototype =~ m/^(\w+\s+\w+\s*\*+\s*\w+\s*\*+\s*)\s*([a-zA-Z0-9_~:]+)\s*\(([^\{]*)\)/)  {
 	$return_type = $1;
 	$declaration_name = $2;
 	my $args = $3;