arch/x86: notify the system when the postcar parameter was updated

While rmodule_load() calls arch_segment_loaded() when it's done
loading any pieces of code which further modify it, like changing
parameters within the program itself, need to notify the rest of
the system.

Change-Id: Ia3374b58488120ba6279592a77d7f9c6217f1215
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/14213
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>

src/arch/x86/postcar_loader.c

@@ -111,5 +111,12 @@ void run_postcar_phase(struct postcar_frame *pcf)
 
 	*(uintptr_t *)rsl.params = pcf->stack;
 
+	/*
+	 * Signal to rest of system that another update was made to the
+	 * postcar program prior to running it.
+	 */
+	arch_segment_loaded((uintptr_t)rsl.params, sizeof(uintptr_t),
+		SEG_FINAL);
+
 	prog_run(&prog);
 }