OMAP3: Enable SPL on omap3_logic

Previously, Omap3_logic assumed X-loader was present.  With this
patch, we can finally replace X-loader with an MLO generated by
U-Boot.  This requires ECC to be setup to match the Linux Kernel
and the PBIAS confgured for the SD card.

Signed-off-by: Derald D. Woods <woods.technical@gmail.com>
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>