x86: fsp: Move common dram functions into a common file

Most of the DRAM functionality can be shared between FSP1 and FSP2. Move
it into a shared file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: rebase the patch against u-boot-x86/next to get it applied cleanly]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
5 files changed