Revert "staging: board: disable as it breaks the build"

This reverts commit d13778d5.

Commit 13c11072 ("staging:board: remove unnecessary function")
fixed the build of drivers/staging/board/board.c.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>