global: renamed cpu-conf.h into cpu_conf.h

boards/native/drivers/native-ltc4150.c

boards/pba-d-01-kw2x/include/periph_conf.h

boards/pttu/include/board.h

boards/qemu-i386/include/cpu_conf.h

boards/udoo/include/board.h

core/include/debug.h

core/include/kernel.h

cpu/atmega2560/include/cpu_conf.h

cpu/atmega_common/include/cpu.h

cpu/cc2538/include/cpu_conf.h

cpu/cortex-m0_common/include/cpu.h

cpu/cortex-m3_common/include/cpu.h

cpu/cortex-m4_common/include/cpu.h

cpu/k60/include/cpu_conf.h

cpu/kinetis_common/cpuid.c

cpu/kinetis_common/hwtimer_arch.c

cpu/kinetis_common/include/hwtimer_cpu.h

cpu/kinetis_common/include/mcg.h

cpu/kinetis_common/startup.c

cpu/kinetis_common/wdog.c