west: sign/rimage: fix rimage argument if --no-manifest

If --no-manifest is specified, '-e' is still being passed
to rimage to build the extended manifest. Fix this so
that when --no-manifest is specified, '-e' is no longer
passed to rimage.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
diff --git a/scripts/west_commands/sign.py b/scripts/west_commands/sign.py
index 28deea7..50927da 100644
--- a/scripts/west_commands/sign.py
+++ b/scripts/west_commands/sign.py
@@ -461,13 +461,18 @@
         else:
             no_manifest = False
 
+        if no_manifest:
+            extra_ri_args = ['-i', '3']
+        else:
+            extra_ri_args = ['-i', '3', '-e']
+
         if 'imx8' in target:
             sign_base = ([tool_path] + args.tool_args +
-                         ['-o', out_bin] +  conf_path_cmd + ['-i', '3', '-e'] +
+                         ['-o', out_bin] + conf_path_cmd + extra_ri_args +
                          [kernel])
         else:
             sign_base = ([tool_path] + args.tool_args +
-                         ['-o', out_bin] +  conf_path_cmd + ['-i', '3', '-e'] +
+                         ['-o', out_bin] + conf_path_cmd + extra_ri_args +
                          [bootloader, kernel])
 
         if not args.quiet: