m68k: Add vmlinux.lds to .gitignore

arch/m68k/kernel/.gitignore: Added vmlinux.lds to .gitignore file because it
shouldn't be tracked.
Signed-off-by: NKars de Jong <jongk@linux-m68k.org>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/kernel/.gitignore

+vmlinux.lds