arm: Remove vision2 board

This board has not been converted to generic board by the deadline.
Remove it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Stefano Babic <sbabic@denx.de>
diff --git a/doc/README.watchdog b/doc/README.watchdog
index 59f306b..b66fd6c 100644
--- a/doc/README.watchdog
+++ b/doc/README.watchdog
@@ -27,6 +27,7 @@
 	Available for i.mx31/35/5x/6x to service the watchdog. This is not
 	automatically set because some boards (vision2) still need to define
 	their own hw_watchdog_reset routine.
+	TODO: vision2 is removed now, so perhaps this can be changed.
 
 CONFIG_XILINX_TB_WATCHDOG
 	Available for Xilinx Axi platforms to service timebase watchdog timer.