fsl-ddr: add the DDR3 SPD infrastructure

- support mirrored DIMMs, not support register DIMMs
- test passed on P2020DS board with MT9JSF12872AY-1G1D1
- test passed on MPC8569MDS board with MT8JSF12864HY-1G1D1

Signed-off-by: Dave Liu <daveliu@freescale.com>
Signed-off-by: Travis Wheatley <travis.wheatley@freescale.com>
10 files changed