The existing code (prior to the patch) does an "ioremap_nocache" on a
subset of a memory region that I think has already been mapped, and then
un-maps that smaller region when it is finished.
Thanks Nathan Hintz for the patch
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@31481 3c298f89-4303-0410-b956-a3cf2f4a3e73
