m68k/mac: Add missing platform check before registering platform devices

m68k/mac: Add missing platform check before registering platform devices

BugLink: http://bugs.launchpad.net/bugs/981162

commit 6cfeba53911d6d2f17ebbd1246893557d5ff5aeb upstream.

On multi-platform kernels, the Mac platform devices should be registered
when running on Mac only. Else it may crash later.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>