m68knommu: no need to set register marker on traps

Commit 61619b12078dc8b85a3d4cbfa16f650daa341bd1 ("m68k: merge mmu and
non-mmu include/asm/entry.h files") made the trap entry code basically
the same for mmu and non-mmu builds. This means we no longer need code
to mark the stack frame as "system-call" type or other in the non-mmu
trap handling entry points. This is done in the SAVE_ALL_INT macro now.

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