arm: ls102xa: Add SystemID EEPROM support for LS1021ATWR board

SystemID information could be read through I2C1 from EEPROM
on LS1021ATWR board.

As LS1 is a little-endian processor, getting the version ID by
be32_to_cpu() is wrong. Fix it by using e.version directly.
This change will be compatible for both ARM and PowerPC.

As there is an errata that I2C1 could not work in SD boot,
reading EEPROM through I2C1 is disabled too in SD boot.

Signed-off-by: Alison Wang <alison.wang@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>