This define seems better suited to the eeprom header file, particularly
as it is only used in the eeprom.c file.

Move it.
Signed-off-by: NSimon Glass <sjg@chromium.org>

These functions do not use driver model but are still used. Move them to a
new eeprom.h header file.
Signed-off-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NTom Rini <trini@konsulko.com>