[Blackfin][PATCH] Add BF537 stamp board support

MAKEALL

Makefile

board/bf537-stamp/Makefile

board/bf537-stamp/bf537-stamp.c

board/bf537-stamp/cmd_bf537led.c

board/bf537-stamp/config.mk

board/bf537-stamp/ether_bf537.c

board/bf537-stamp/ether_bf537.h

board/bf537-stamp/flash-defines.h

board/bf537-stamp/flash.c

board/bf537-stamp/nand.c

board/bf537-stamp/post-memory.c

board/bf537-stamp/stm_m25p64.c

board/bf537-stamp/u-boot.lds.S

cpu/bf537/Makefile

cpu/bf537/cache.S

cpu/bf537/config.mk

cpu/bf537/cpu.c

cpu/bf537/cpu.h

cpu/bf537/flush.S