Shifting them up into the vmalloc region prevents the following warning,
when booting a zynq qemu target with more than 512mb of RAM:

  BUG: mapping for 0xe0000000 at 0xe0000000 out of vmalloc space

In addition, it allows for reuse of these mappings when the proper
drivers issue requests via ioremap().

There are currently unknown issues with the early uart mapping.  For
now, the uart will be mapped to a known working address.
Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Cc: John Linn <john.linn@xilinx.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Michal Simek <michal.simek@xilinx.com>