depends.py: Add warning log

Add warning log when disabling a configuration
option that does not exist.

When the removal of the legacy crypto config
options is completed, the warning will be
reverted to an error.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/scripts/depends.py b/tests/scripts/depends.py
index 08829d1..7fccb20 100755
--- a/tests/scripts/depends.py
+++ b/tests/scripts/depends.py
@@ -110,6 +110,10 @@
 which will make a symbol defined with a certain value."""
     if not option_exists(conf, option):
         if value is False:
+            log_line(
+                f'Warning, disabling {option} that does not exist in {conf.filename}',
+                color=colors.cyan
+            )
             return True
         log_line('Symbol {} was not found in {}'.format(option, conf.filename), color=colors.red)
         return False