The AMCC Luan now uses the common 440SP(e) DDR SPD code for DDR
inititializition. This includes DDR auto calibration and support
for different DIMM modules, instead of the fixed setup used in
the earlier version.

This patch also enables the cache in FLASH for the startup
phase of U-Boot (while running from FLASH). After relocating to
SDRAM the cache is disabled again. This will speed up the boot
process, especially the SDRAM setup, since there are some loops
for memory testing (auto calibration).

Signed-off-by: Stefan Roese <sr@denx.de>