board/orangepi-zero-plus: update link in readme

Old link is no longer working, so use new link instead.

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 0612504c4301b3aed4757d9358dd5b5cf09ef1cf)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/orangepi/orangepi-zero-plus/readme.txt

@@ -6,7 +6,7 @@ buildroot environment for the Orangepi Zero Plus. With the current configuration
 it will bring-up the board, and allow access through the serial console.
 
 Orangepi Zero Plus link:
-http://www.orangepi.org/OrangePiZeroPlus/
+http://www.orangepi.org/html/hardWare/computerAndMicrocontrollers/details/Orange-Pi-Zero-Plus.html
 
 This configuration uses U-Boot mainline and kernel mainline.