ARM: rpi: rename rpi_b to rpi

The U-Boot port runs on a variety of RPi models, not just the B. So,
rename the port to something slightly more generic.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/board/raspberrypi/rpi/MAINTAINERS b/board/raspberrypi/rpi/MAINTAINERS
new file mode 100644
index 0000000..6dcb7bd
--- /dev/null
+++ b/board/raspberrypi/rpi/MAINTAINERS
@@ -0,0 +1,6 @@
+RPI BOARD
+M:	Stephen Warren <swarren@wwwdotorg.org>
+S:	Maintained
+F:	board/raspberrypi/rpi/
+F:	include/configs/rpi.h
+F:	configs/rpi_defconfig