sphinx: rename top level document in each manual

It is more common to call the top level document index.rst. This is
what this patch is doing, along with all required references fixup.

(From yocto-docs rev: 2cea7fbba9210479fc0387d7e1b80da9885558f0)

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 0 insertions, 0 deletions

diff --git a/documentation/bsp-guide/bsp-guide.rst b/documentation/bsp-guide/index.rst
index a4394a85ed..a4394a85ed 100644
--- a/documentation/bsp-guide/bsp-guide.rst
+++ b/documentation/bsp-guide/index.rst