ia64: rename ioremap_nocache to ioremap_uc

On ia64 ioremap_nocache fails if attributes 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
anyway.

However x86 implements ioremap_uc in a similar way as the ia64
version of ioremap_nocache, in that it ignores the firmware tables.
Switch ia64 to override ioremap_uc instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>