m68k: Simplify ioremap_nocache()

Just define ioremap_nocache to ioremap instead of duplicating the
inline.  Also define ioremap_uc in terms of ioremap instead of
using a double indirection.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20190817073253.27819-9-hch@lst.de


Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>