cpu/amd: Add initial AMD Family 15h support

TEST: Booted ASUS KGPE-D16 with single Opteron 6380
 * Unbuffered DDR3 DIMMs tested and working
 * Suspend to RAM (S3) tested and working

Change-Id: Idffd2ce36ce183fbfa087e5ba69a9148f084b45e
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/11966
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
73 files changed