On ia64 ioremap_nocache fails if attributs don't match. Not other
architectures does this, and we plan to get rid of ioremap_nocache.
So get rid of the special semantics and define ioremap_nocache in
terms of ioremap as no portable driver could rely on the behavior
However x86 implements ioremap_uc with a in a similar way as the ia64
version of ioremap_nocache, so implement that instead.[...]
Signed-off-by: Christoph Hellwig <hch@xxxxxx>