Adapt make cscope

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/Makefile b/Makefile
index b638804..d281dec 100644
--- a/Makefile
+++ b/Makefile
@@ -216,6 +216,7 @@
 	tests/include/*/*.h tests/include/*/*/*.h \
 	tests/src/*.c tests/src/*/*.c \
 	tests/suites/*.function \
+	tf-psa-crypto/tests/suites/*.function \
 )
 # Exuberant-ctags invocation. Other ctags implementations may require different options.
 CTAGS = ctags --langmap=c:+.h.function --line-directives=no -o