serial: sirf: add support for new SiRFmarco SMP SoC

CSR SiRFmarco's UART IP is same with SiRFprimaII except that
it has two more uart ports.
this patch makes the old driver support new SiRFmarco as well:
1. add .compatible = "sirf,marco-uart" to OF match table
2. add two ports in the port table
3. take spin_lock in isr to avoid the conflict of threads opening
uart on CPU1 and isr running on CPU0.
For 3, we did see some problems on SiRFmarco as SiRFmarco is a
SMP SoC but the old SiRFprimaII is UP.

Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>