drivers/amd/agesa: Assert that StdHeader is non-null

Coverity believes there is a path where StdHeader is possibly
null. This *should* be incorrect, since the header is actually
initialized through the module dispatch framework, though Coverity
can't see it due to the extensive type-punning. However, the control
flow is so dizzingly complicated that I'm not even completely sure,
so adding an extra assert to be careful won't hurt anyway.

Change-Id: If3d7c5d5c5bba846e7453b3dbc824e2208d749fb
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 1379932
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33214
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
diff --git a/src/drivers/amd/agesa/state_machine.c b/src/drivers/amd/agesa/state_machine.c
index c8529c5e..750d192 100644
--- a/src/drivers/amd/agesa/state_machine.c
+++ b/src/drivers/amd/agesa/state_machine.c
@@ -272,7 +272,7 @@
 
 	/* Must call the function buffer was allocated for.*/
 	AMD_CONFIG_PARAMS *StdHeader = aip.NewStructPtr;
-	ASSERT(StdHeader->Func == func);
+	ASSERT(StdHeader != NULL && StdHeader->Func == func);
 
 	if (CONFIG(AGESA_EXTRA_TIMESTAMPS) && task.ts_entry_id)
 		timestamp_add_now(task.ts_entry_id);