Input: raydium_ts_i2c - do not send zero length

Add default write command package to prevent i2c quirk error of zero
data length as Raydium touch firmware update is executed.
Signed-off-by: jeffrey.lin <jeffrey.lin@rad-ic.com>
Link: https://lore.kernel.org/r/1608031217-7247-1-git-send-email-jeffrey.lin@raydium.corp-partner.google.com
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/raydium_i2c_ts.c

@@ -395,6 +395,7 @@ static int raydium_i2c_write_object(struct i2c_client *client,
 				    enum raydium_bl_ack state)
 {
 	int error;
+	static const u8 cmd[] = { 0xFF, 0x39 };
 
 	error = raydium_i2c_send(client, RM_CMD_BOOT_WRT, data, len);
 	if (error) {
@@ -403,7 +404,7 @@ static int raydium_i2c_write_object(struct i2c_client *client,
 		return error;
 	}
 
-	error = raydium_i2c_send(client, RM_CMD_BOOT_ACK, NULL, 0);
+	error = raydium_i2c_send(client, RM_CMD_BOOT_ACK, cmd, sizeof(cmd));
 	if (error) {
 		dev_err(&client->dev, "Ack obj command failed: %d\n", error);
 		return error;