soc/amd: factor out common SMI/SCI enums and function prototypes

At least a part or the remaining definitions in the soc-specific smi.h
files are also common, but those have to be verified more closely.

Change-Id: I5a3858e793331a8d2ec262371fa22abac044fd4a
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48217
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/mainboard/google/kahlee/mainboard.c

@@ -8,6 +8,7 @@
 #include <acpi/acpi_gnvs.h>
 #include <amdblocks/agesawrapper.h>
 #include <amdblocks/amd_pci_util.h>
+#include <amdblocks/smi.h>
 #include <baseboard/variants.h>
 #include <boardid.h>
 #include <smbios.h>

src/mainboard/google/zork/mainboard.c

@@ -10,6 +10,7 @@
 #include <acpi/acpi_gnvs.h>
 #include <amdblocks/amd_pci_util.h>
 #include <amdblocks/gpio_banks.h>
+#include <amdblocks/smi.h>
 #include <baseboard/variants.h>
 #include <boardid.h>
 #include <gpio.h>