drm/bridge/sii8620: add remote control support

MHL specification defines Remote Control Protocol(RCP) to
send input events between MHL devices.
The driver now recognizes RCP messages and reacts to them
by reporting key events to input subsystem, allowing
a user to control a device using TV remote control.

Signed-off-by: Maciej Purski <m.purski@samsung.com>
Acked-by: Sean Young <sean@mess.org>
Acked-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1503565087-19730-1-git-send-email-m.purski@samsung.com
diff --git a/include/drm/bridge/mhl.h b/include/drm/bridge/mhl.h
index fbdfc8d..96a5e0f 100644
--- a/include/drm/bridge/mhl.h
+++ b/include/drm/bridge/mhl.h
@@ -262,6 +262,10 @@ enum {
 #define MHL_RAPK_UNSUPPORTED	0x02	/* Rcvd RAP action code not supported */
 #define MHL_RAPK_BUSY		0x03	/* Responder too busy to respond */
 
+/* Bit masks for RCP messages */
+#define MHL_RCP_KEY_RELEASED_MASK	0x80
+#define MHL_RCP_KEY_ID_MASK		0x7F
+
 /*
  * Error status codes for RCPE messages
  */