ARM: SAMSUNG: Include most of mach/ headers conditionally

Since it is illegal to include mach/ headers from source files outside
of respective mach-* directory and DT-only Samsung platforms might not
have all of them anyway, this patches makes inclusion of them
conditional, based on CONFIG_SAMSUNG_ATAGS.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>