rpi: Add identifier for the new RPi3 B+

The Raspberr Pi Foundation released a new RPi3 version which we want
to detect as well, so we can enable ethernet on it and know the correct
device tree file name.

Add an identifier for it.

Signed-off-by: Alexander Graf <agraf@suse.de>

board/raspberrypi/rpi/rpi.c

@@ -111,6 +111,11 @@ static const struct rpi_model rpi_models_new_scheme[] = {
 		DTB_DIR "bcm2835-rpi-zero-w.dtb",
 		false,
 	},
+	[0xD] = {
+		"3 Model B+",
+		DTB_DIR "bcm2837-rpi-3-b-plus.dtb",
+		true,
+	},
 };
 
 static const struct rpi_model rpi_models_old_scheme[] = {