powerpc/mpc8xxx: Enable 3-way and 4-way DDR interleaving

Restructure DDR interleaving option to support 3 and 4 DDR controllers
for 2-, 3- and 4-way interleaving.

Signed-off-by: York Sun <yorksun@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
10 files changed