ARM: sirf: add Atlas7 machine support

CSRatlas7 is next-gen auto SoC from CSR.
It could bring to customers most integrated SoC solution:
- World leading Bluetooth 4.0 and GNSS baseband
- Audio processing, analog CODEC and ADC by DSP
- Analog video input
- SDR accelerators
- CAN bus support by Cortex-M3

Signed-off-by: Zhiwu Song <Zhiwu.Song@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>