drm/mipi_dsi: add flags to DSI messages

This patch adds flags field to mipi_dsi_msg structure and two flags:
- MIPI_DSI_MSG_REQ_ACK - request ACK from peripheral for given message,
- MIPI_DSI_MSG_USE_LPM - use Low Power Mode to transmit message.
The first flag is usually helpful during DSI diagnostic, the second
flag is required by some peripherals during configuration phase.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

include/drm/drm_mipi_dsi.h

@@ -17,6 +17,11 @@
 struct mipi_dsi_host;
 struct mipi_dsi_device;
 
+/* request ACK from peripheral */
+#define MIPI_DSI_MSG_REQ_ACK	BIT(0)
+/* use Low Power Mode to transmit message */
+#define MIPI_DSI_MSG_USE_LPM	BIT(1)
+
 /**
  * struct mipi_dsi_msg - read/write DSI buffer
  * @channel: virtual channel id
@@ -29,6 +34,7 @@ struct mipi_dsi_device;
 struct mipi_dsi_msg {
 	u8 channel;
 	u8 type;
+	u16 flags;
 
 	size_t tx_len;
 	const void *tx_buf;