ks2_evm: Add EEPROM based board detection

Some K2G evms have their EEPROM programming while most do not. Therefore,
add EEPROM board detection to be used as the default method and fall back
to the alternative board detection when needed.

Also reorder board configuration. Perform bare minimal configuration
initially since board detection hasn't ran. Finish board configuration
once the board has been identified.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>