The isa region is not exposed as a sysbus region because the iobr
register contains its address and use it to remap dynamically
the region. (Peter Maydell's idea)
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NBenoît Canet <benoit.canet@gmail.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>