keystone: ddr3: add ddr3.h to hold ddr3 API

It's convinient to hold ddr3 function definitions in separate file
such as ddr3.h. So move this from hardware.h to ddr3.h.

Acked-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
5 files changed