PTY: add kernel parameter to overwrite legacy pty count

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a57c1f2..bdddd3c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1430,6 +1430,10 @@
 	pt.		[PARIDE]
 			See Documentation/paride.txt.
 
+	pty.legacy_count=
+			[KNL] Number of legacy pty's. Overwrites compiled-in
+			default number.
+
 	quiet		[KNL] Disable most log messages
 
 	r128=		[HW,DRM]