drm/r128: fix r128 ioremaps to use ioremap_wc.

commit 42beefc0 upstream.

This should allow r128 to start working again since PAT changes.

taken from F-11 kernel.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>