Input: serio - add support for PS2Mult multiplexer protocol

PS2Mult is a simple serial protocol used for multiplexing several PS/2
streams into one serial data stream. It's used e.g. on TQM85xx series
of boards.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/include/linux/serio.h b/include/linux/serio.h
index 109b237..e26f478 100644
--- a/include/linux/serio.h
+++ b/include/linux/serio.h
@@ -198,5 +198,6 @@
 #define SERIO_W8001	0x39
 #define SERIO_DYNAPRO	0x3a
 #define SERIO_HAMPSHIRE	0x3b
+#define SERIO_PS2MULT	0x3c
 
 #endif