Initial support for MPC8641 HPCN board.

Makefile

board/mpc8641hpcn/Makefile

board/mpc8641hpcn/config.mk

board/mpc8641hpcn/flash.c

board/mpc8641hpcn/init.S

board/mpc8641hpcn/mpc8641hpcn.c

board/mpc8641hpcn/oftree.dts

board/mpc8641hpcn/u-boot.lds

common/ft_build.c

cpu/mpc86xx/Makefile

cpu/mpc86xx/cache.S

cpu/mpc86xx/config.mk

cpu/mpc86xx/cpu.c

cpu/mpc86xx/cpu_init.c

cpu/mpc86xx/i2c.c

cpu/mpc86xx/interrupts.c

cpu/mpc86xx/pci.c

cpu/mpc86xx/resetvec.S

cpu/mpc86xx/spd_sdram.c

cpu/mpc86xx/speed.c