Standardize command usage messages with cmd_usage()

board/BuS/EB+MCF-EV123/EB+MCF-EV123.c

board/ads5121/ads5121_diu.c

board/amcc/acadia/cmd_acadia.c

board/amcc/canyonlands/bootstrap.c

board/amcc/katmai/cmd_katmai.c

board/amcc/kilauea/cmd_pll.c

board/amcc/luan/luan.c

board/amcc/makalu/cmd_pll.c

board/amcc/sequoia/cmd_sequoia.c

board/amcc/yucca/cmd_yucca.c

board/barco/barco.c

board/esd/common/lcd.c

board/esd/dasa_sim/cmd_dasa_sim.c

board/freescale/common/sys_eeprom.c

board/freescale/mpc8610hpcd/mpc8610hpcd_diu.c

board/hymod/bsp.c

board/lwmon/lwmon.c

board/lwmon5/lwmon5.c

board/mpl/common/common_util.c

board/pcippc2/pcippc2.c