This code calculates the DIMM characteritics i.e DIMM
organization parameters and timings for DDR2 memory based on
SPD data.

It also provides a function to find out the lowest common DIMM
parameters to be used for all DIMMs.

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>