ARM: rpi: add another revision of Raspberry Pi A+

Seen this one in the wild. Is labelled "Raspberry Pi Model A+ V1.1,
(C) Raspberry Pi 2014". A standard A+ board, much like the one with
version 0x12, didn't notice any differencies.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
diff --git a/board/raspberrypi/rpi/rpi.c b/board/raspberrypi/rpi/rpi.c
index 6d7be11..942badb 100644
--- a/board/raspberrypi/rpi/rpi.c
+++ b/board/raspberrypi/rpi/rpi.c
@@ -176,6 +176,11 @@
 		"bcm2835-rpi-cm.dtb",
 		false,
 	},
+	[BCM2835_BOARD_REV_A_PLUS_15] = {
+		"Model A+",
+		"bcm2835-rpi-a-plus.dtb",
+		false,
+	},
 #endif
 };