Addition of Family12/SB900 wrapper code

Addition of Family12/SB900 wrapper code

This change adds the wrapper code for the AMD Family12
cpus and the AMD Hudson-2 (SB900) southbridge to the cpu,
northbridge and southbridge folders respectively.

Change-Id: I22b6efe0017d0af03eaa36a1db1615e5f38da06c
Signed-off-by: Frank Vibrans <frank.vibrans@amd.com>
Signed-off-by: efdesign98 <efdesign98@gmail.com>
Reviewed-on: http://review.coreboot.org/53
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>