soc/amd/picasso: add psp_verstage

This is the main code for building coreboot's verstage as a userspace
application to run on the PSP.  It does a minimal setup of hardware,
then runs verstage_main.  It uses hardware hashing to increase the speed
and will directly reboot into recovery mode if there are any failures.

BUG=b:158124527
TEST=Build & boot trembyle

Signed-off-by: Martin Roth <martin@coreboot.org>
Change-Id: Ia58839caa5bfbae0408702ee8d02ef482f2861c4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41816
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>

src/soc/amd/picasso/chip.h

@@ -12,7 +12,7 @@
 #include <soc/iomap.h>
 #include <soc/southbridge.h>
 #include <acpi/acpi_device.h>
-#include <arch/smp/mpspec.h>
+#include <arch/x86/include/arch/smp/mpspec.h> /* point from top level */
 
 /*
   USB 2.0 PHY Parameters