arm: prima2: add new SiRFatlas6 machine in common board

SiRFatlas6's machine definition is almost seem with SiRFprimaII
except that prima2 has a 256MB DMA zone.
This patch adds SiRFatlas6 machine in common board files, and
also adds atlas6 arch node in Kconfig.

Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2 files changed