kernel-doc: reset contents and section harder

If the documentation comment does not have params or sections, the
section heading may leak from the previous documentation comment.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index 3ac4b57..0eb2e7b 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -2763,6 +2763,8 @@
 		}
 
 		$state = STATE_FIELD;
+		$contents = "";
+		$section = $section_default;
 		if (/-(.*)/) {
 		    # strip leading/trailing/multiple spaces
 		    $descr= $1;
@@ -2960,6 +2962,7 @@
 		elsif (/$doc_end/)
 		{
 			dump_doc_section($file, $section, xml_escape($contents));
+			$section = $section_default;
 			$contents = "";
 			$function = "";
 			%parameterdescs = ();