drivers/ddr/fsl: Modify binding registers to save time on data init

drivers/ddr/fsl: Modify binding registers to save time on data init

DDR controllers always use binding register to determine the memory
space to perform data initialization. In case of controller interleaving,
the space is doubled, resulting twice long wait. It wasn't too bad until
the memory capacity increases. To reduce the wait time, reduce the
binding space to half and restore it after data initialization.
Three-way interleaving is no longer used and is removed.

Signed-off-by: York Sun <york.sun@nxp.com>