The user mode architecture does not provide ioremap or iounmap, and
because of this, the arch won't build when the functions are used in some
core libraries.

I have designs to use these functions in scatterlist.c where they'd
almost certainly never be called on the um architecture but it does need
to compile.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Stephen Bates <sbates@raithlin.com>
Signed-off-by: Richard Weinberger <richard@nod.at>