moveoff: rtai: no use struct for lim3() outputs

worked with rt-preempt, uspace
but did not work with:

dgarr:  vmlinuz-3.4-9-rtai-686-pae
        ii  linux-image-3.4-9-rtai-686-pae 3.4.55-4linuxcnc

nor with:
JT: vmlinuz-2.6.32-122-rtai

so use pointers instead

Signed-off-by: Dewey Garrett <dgarrett@panix.com>