m68k: Move cpu/$CPU to arch/m68k/cpu/$CPU

arch/m68k/cpu/mcf5227x/Makefile

arch/m68k/cpu/mcf5227x/config.mk

arch/m68k/cpu/mcf5227x/cpu.c

arch/m68k/cpu/mcf5227x/cpu_init.c

arch/m68k/cpu/mcf5227x/interrupts.c

arch/m68k/cpu/mcf5227x/speed.c

arch/m68k/cpu/mcf5227x/start.S

arch/m68k/cpu/mcf523x/Makefile

arch/m68k/cpu/mcf523x/config.mk

arch/m68k/cpu/mcf523x/cpu.c

arch/m68k/cpu/mcf523x/cpu_init.c

arch/m68k/cpu/mcf523x/interrupts.c

arch/m68k/cpu/mcf523x/speed.c

arch/m68k/cpu/mcf523x/start.S

arch/m68k/cpu/mcf52x2/Makefile

arch/m68k/cpu/mcf52x2/config.mk

arch/m68k/cpu/mcf52x2/cpu.c

arch/m68k/cpu/mcf52x2/cpu.h

arch/m68k/cpu/mcf52x2/cpu_init.c

arch/m68k/cpu/mcf52x2/interrupts.c