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>

src/include/cpu/amd/car.h

@@ -10,7 +10,7 @@ void post_cache_as_ram(void);
 void cache_as_ram_switch_stack(void *stacktop);
 void cache_as_ram_new_stack(void);
 
-#if CONFIG_CPU_AMD_AGESA || CONFIG_CPU_AMD_PI
+#if CONFIG_CPU_AMD_AGESA || CONFIG_CPU_AMD_PI || CONFIG_SOC_AMD_PI
 void disable_cache_as_ram(void);
 #endif