MAINTAINERS: drop bcm283x/rpi maintainership

It's been a while since I've touched U-Boot on the Raspberry Pi and
other things have been taking my time. Drop my maintainership for this
port.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
diff --git a/board/raspberrypi/rpi/MAINTAINERS b/board/raspberrypi/rpi/MAINTAINERS
index 98c3758..a7eb365 100644
--- a/board/raspberrypi/rpi/MAINTAINERS
+++ b/board/raspberrypi/rpi/MAINTAINERS
@@ -1,6 +1,6 @@
 RPI BOARD
-M:	Stephen Warren <swarren@wwwdotorg.org>
-S:	Maintained
+#M:	Stephen Warren <swarren@wwwdotorg.org>
+S:	Orphaned (Since 2017-07)
 F:	board/raspberrypi/rpi/
 F:	include/configs/rpi.h
 F:	configs/rpi_*defconfig