Commit ad7061ed74 ("doc: Move device tree bindings documentation to
doc/device-tree-bindings") moved all device tree binding documentation
to doc/device-tree-bindings directory.
The current U-Boot project still have two documentation directories:
- doc/
- Documentation/
Move all documentation and sphinx files to doc directory so all content
can be in a common place.
Signed-off-by: Breno Lima <breno.lima@nxp.com>