soc/amd/stoneyridge: Add CPU files

Copy cpu/amd/pi/00670F00 to soc/amd/stoneyridge and
soc/amd/common.  This is the second patch in the process of
converting Stoney Ridge to soc/.

Changes:
- update Kconfig and Makefiles
- update vendorcode/amd for new soc/ path

Change-Id: I8b6b1991372c2c6a02709777a73615a86e78ac26
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: https://review.coreboot.org/19723
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/northbridge/amd/pi/Kconfig b/src/northbridge/amd/pi/Kconfig
index f5f36f8..49e915f 100644
--- a/src/northbridge/amd/pi/Kconfig
+++ b/src/northbridge/amd/pi/Kconfig
@@ -15,7 +15,9 @@
 
 config NORTHBRIDGE_AMD_PI
 	bool
-	default CPU_AMD_PI
+	default y if CPU_AMD_PI
+	default y if SOC_AMD_PI
+	default n
 	select LATE_CBMEM_INIT
 
 if NORTHBRIDGE_AMD_PI