kernel-doc: prevent duplicate description: output

Prevent duplicate output of a Description: section when there is a "blank"
("*") line between the initial function name/description line and the
"Description:" header.

Test case:  drivers/scsi/scsi_devinfo.c::scsi_init_devinfo().

Rob Landley hit this while he was producing SCSI kernel-doc.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

scripts/kernel-doc

@@ -1907,7 +1907,7 @@ sub process_file($) {
 		$newsection = $1;
 		$newcontents = $2;
 
-		if ($contents ne "") {
+		if (($contents ne "") && ($contents ne "\n")) {
 		    if (!$in_doc_sect && $verbose) {
 			print STDERR "Warning(${file}:$.): contents before sections\n";
 			++$warnings;