As per the maintainers at egnite GmbH, they are no longer interested in
supporting this board. Go and remove the platform here. Furthermore,
this is the only AT91SAM9XE platform in-tree so remove supporting code
for that as well.

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>

These board index.rst files are missing in previous html doc patch
series, hence it causes some build warnings. Add those files.

Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

Convert plain text documentation to reStructuredText format and add
it to Sphinx TOC tree. No essential content change.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>