sandbox: Migrate CONFIG_I2C_EEPROM

Most users of CONFIG_I2C_EEPROM were migrated to defconfig a while ago,
but sandbox was skipped.  Leave it off for sandbox_spl where it does not
build, but does not need to be either.

Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>