sh: pass through ioremap() for non-mmu processors.

All 32-bit SuperH processors currently go through __ioremap_mode()
and check for IO_TRAPPED and directly mapped segments. With this
patch we simplify the MMU less case with a pass through version of
 __ioremap_mode() which just returns the physical address.

The effects of this is change are:
 - fix non-MMU ioremap() of high address hardware blocks (sh7203 CMT)
 - make sure IO_TRAPPED is not selected

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>