This commit adds functions to calculate clock cycles, configure the
LAW registers and populate board memory options.
This code is based on the equivalent files in directory
arch/powerpc/cpu/mpc8xxx/ddr from U-Boot version git-a71d45d.
Signed-off-by: Renaud Barbier <renaud.barbier@ge.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>