ARM: zynq: Reserve not DMAable space in front of the kernel

Reserve space from 0x0 - __pa(swapper_pg_dir),
if kernel is loaded from 0, which is not DMAable.
It is causing problem with MMC driver and others
which want to add dma buffers to this space.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>