uboot-imx

drivers/ddr/fsl: Enable detection of one DDR controller operation for LSCH3

Freescale LSCH3 platforms use two DDR controlers interleaving mode out of
reset. It can be configured to disable one controller. To support this
operation, the driver needs to detect and skip the disabled controller.

Signed-off-by: York Sun <yorksun@freescale.com>