arm: omap3: Add SPL support to cm_t35

Add SPL U-Boot support to replace x-loader on the Compulab cm_t35
board. Currently only the 256MiB SDRAM board versions are supported.

Tested by booting via MMC and NAND.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Tom Rini <trini@ti.com>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Cc: Nikita Kiryanov <nikita@compulab.co.il>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>