m68knommu: fix rename of pt_regs offset defines breakage

Commit f159ee78 ("locking,
m68k/asm-offsets: Rename pt_regs offset defines") breaks the
m68knommu entry code that relies on these define names.
Fix the files to match the new define names.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>