This hides the option for people who do not want their Kconfig
vision cluttered (i.e. x86) and enables compile testing apart
from the supported main arch.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>