ucc_uart: add support for Freescale QUICCEngine UART

[Scott Wood]

Arnd Bergmann wrote:
> From a code clarity perspective, the interesting point is that dma_addr_t is
> what comes back from the functions in dma-mapping.h. If you don't use them,
> a physical address is phys_addr_t.
> 
> You can argue that the QS is really a DMA device, but in that case you
> should convert the driver to use the DMA mapping interfaces correctly,
> which I would consider overkill.

Why is it overkill?

-Scott