target-m68k: define m680x0 CPUs and features

target-m68k: define m680x0 CPUs and features

This patch defines height new features:

    - M68K_FEATURE_SCALED_INDEX, scaled address index register
    - M68K_FEATURE_LONG_MULDIV, 32bit multiply/divide
    - M68K_FEATURE_QUAD_MULDIV, 64bit multiply/divide
    - M68K_FEATURE_BCCL, long conditional branches
    - M68K_FEATURE_BITFIELD, bit field instructions
    - M68K_FEATURE_FPU, FPU instructions
    - M68K_FEATURE_CAS, cas instruction
    - M68K_FEATURE_BKPT, bkpt instruction

Original patch from Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>