m68knommu: __force type casts for raw IO access

Bring the m68knommu raw IO functions into line with the m68k raw IO
access functions and __force casting of the address component. This
is primarily to fix sparse warnings on use of these raw macros.

Reported-by: kernel test robot <lkp@intel.com>
CC: Marc Kleine-Budde <mkl@pengutronix.de>
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>