cpu/x86: add AMD registers to SMM save state

In amd64_smm_state_save_area_t break out fields in reserved4 to allow access.

BUG=b:65485690

Change-Id: I592fbf18c166dc1890010dde29f76900a6849016
Signed-off-by: John E. Kabat Jr <john.kabat@scarletltd.com>
Reviewed-on: https://review.coreboot.org/22092
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/include/cpu/x86/smm.h

@@ -90,7 +90,12 @@ typedef struct {
 	u32	tr_limit;
 	u64	tr_base;
 
-	u8	reserved4[40];
+	u64	io_restart_rip;
+	u64	io_restart_rcx;
+	u64	io_restart_rsi;
+	u64	io_restart_rdi;
+	u32	smm_io_trap_offset;
+	u32	local_smi_status;
 
 	u8	io_restart;
 	u8	autohalt_restart;