Add a common get_ram_size() function and modify the the

CHANGELOG

board/LEOX/elpt860/elpt860.c

board/RPXClassic/RPXClassic.c

board/RPXlite/RPXlite.c

board/RRvision/RRvision.c

board/a3000/a3000.c

board/atc/atc.c

board/c2mon/c2mon.c

board/cpc45/cpc45.c

board/cpu86/cpu86.c

board/cu824/cu824.c

board/esteem192e/esteem192e.c

board/etin/debris/debris.c

board/etx094/etx094.c

board/fads/fads.c

board/genietv/genietv.c

board/hermes/hermes.c

board/icecube/icecube.c

board/icu862/icu862.c

board/incaip/incaip.c