kernel-doc: handle varargs cleanly

The method for listing varargs in kernel-doc notation is:
 * @...: these arguments are printed by the @fmt argument

but scripts/kernel-doc is confused:  it always lists varargs as:
	...	variable arguments
and ignores the @...: line's description, but then prints that
line after the list of function parameters as though it's
not part of the function parameters.

This patch makes kernel-doc print the supplied @...  description if it is
present; otherwise a boilerplate "variable arguments" is printed.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/kernel-doc

@@ -378,6 +378,10 @@ sub dump_section {
 #	print STDERR "parameter def '$1' = '$contents'\n";
 	$name = $1;
 	$parameterdescs{$name} = $contents;
+    } elsif ($name eq "@\.\.\.") {
+#	print STDERR "parameter def '...' = '$contents'\n";
+	$name = "...";
+	$parameterdescs{$name} = $contents;
     } else {
 #	print STDERR "other section '$name' = '$contents'\n";
 	if (defined($sections{$name}) && ($sections{$name} ne "")) {
@@ -1588,12 +1592,12 @@ sub push_parameter($$$) {
 
 	if ($type eq "" && $param =~ /\.\.\.$/)
 	{
-	    $type="";
+	    if (!defined $parameterdescs{$param} || $parameterdescs{$param} eq "") {
 		$parameterdescs{$param} = "variable arguments";
 	    }
+	}
 	elsif ($type eq "" && ($param eq "" or $param eq "void"))
 	{
-	    $type="";
 	    $param="void";
 	    $parameterdescs{void} = "no arguments";
 	}