The paging system which is required to set up caching properties has not
yet been initialized when the SDRAM is initialized. So when the
map_physmem() function is converted to return the physical address
unchanged, the SDRAM initialization will break on some boards.
The avr32-specific uncached() macro will return an address which will
always cause uncached accessed to be made. Since this happens in the
board code, using avr32-specific features should be ok, and will allow
the SDRAM initialization to keep working.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>