soc/amd/common/psp: Move definitions into a private file

Declutter psp.h by removing internal details the caller doesn't
need to know.

BUG=b:130660285
TEST: Verify PSP functionality on google/grunt

Change-Id: I2fb0ed1d2697c313fb8475e3f00482899e729130
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://chromium-review.googlesource.com/2020366
Tested-by: Eric Peers <epeers@google.com>
Reviewed-by: Eric Peers <epeers@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40015
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/common/block/psp/psp.c b/src/soc/amd/common/block/psp/psp.c
index 7ec8d7b..c580803 100644
--- a/src/soc/amd/common/block/psp/psp.c
+++ b/src/soc/amd/common/block/psp/psp.c
@@ -24,6 +24,7 @@
 #include <amdblocks/psp.h>
 #include <soc/iomap.h>
 #include <soc/northbridge.h>
+#include "psp_def.h"
 
 static const char *psp_status_nobase = "error: PSP BAR3 not assigned";
 static const char *psp_status_halted = "error: PSP in halted state";