CRIS: add pgprot_noncached

On CRIS, the high address bit controls caching, which means that
we can add a pgprot_noncached() macro that sets this bit in the
address.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>