arch: add basic m68k support

Signed-off-by: Remy Bohmer <linux@bohmer.net>
[yann.morin.1998@anciens.enib.fr: use defaults for CT_TARGET_ARCH]
Signed-off-by: "Yann E. MORIN <yann.morin.1998@anciens.enib.fr>

# Compute M68k-specific values

CT_DoArchTupleValues() {

    :

}