All traditional board files except for MACH_WLF_CRAGG_6410 were
marked as unused, so remove them now.

Cc: Kwangwoo Lee <kwangwoo.lee@gmail.com>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Darius Augulis <augulis.darius@gmail.com>
Cc: Maurus Cuelenaere <mcuelenaere@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>