The following definitions that deal with the placement and management
of environment data (variable area); in general, we support the
following configurations:

- CFG_ENV_IS_IN_FLASH:

 Define this if the environment is in flash memory.

 a) The environment occupies one whole flash sector, which is
    'embedded' in the text segment with the U-Boot code. This
    happens usually with 'bottom boot sector' or 'top boot
    sector' type flash chips, which have several smaller
    sectors at the start or the end. For instance, such a
    layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
    such a case you would