flashrom: fix chip->read in read_flash and write_flash

chip->read() is filling the buffer without an offset.
read does `buf[0] = data of start' and NOT buf[start] = data of start
verify_flash: fix missing offset for buffer - same misuse like chip->read
write_flash: wrong buffer when reading old contents
flashrom: fix indention of boardmismatch block
cli_classic: remove (layout & read) is not supported error
flashrom: allow write_flash without erase_it bit

erase is a different function than write. erase means only erase chip, but not write any data onto