ARM: clps711x: Used own subarch directory for store header file

There is no reason to have the clps7111.h header in a globally
visible location, so move it to a place that is only visible when
building for mach-clps711x.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>