west: sign/rimage: skip extended manifest when !SOF

Non-SOF build does not have extended manifest data for
rimage to process, which might result in rimage error.
So do not do extended manifest during signing when not
doing SOF builds.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
diff --git a/scripts/west_commands/sign.py b/scripts/west_commands/sign.py
index 2c2692c..87b8346 100644
--- a/scripts/west_commands/sign.py
+++ b/scripts/west_commands/sign.py
@@ -517,6 +517,13 @@
         else:
             no_manifest = False
 
+        # Non-SOF build does not have extended manifest data for
+        # rimage to process, which might result in rimage error.
+        # So skip it when not doing SOF builds.
+        is_sof_build = build_conf.getboolean('CONFIG_SOF')
+        if not is_sof_build:
+            no_manifest = True
+
         if no_manifest:
             extra_ri_args = [ ]
         else: