powerpc/t1040qds: Update DDR option

Enable interactive debugging by default. Remove DDR controller interleaving
because this SoC only has one controller. Use auto chip-select interleaving
to detect number of ranks.

Signed-off-by: York Sun <yorksun@freescale.com>
CC: Poonam Aggrwal <poonam.aggrwal@freescale.com>