programs: update .gitignore

Remove entry for benchmark program since it was moved to the tf-psa-crypto
repo.

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/programs/.gitignore b/programs/.gitignore
index c3e61c1..939e405 100644
--- a/programs/.gitignore
+++ b/programs/.gitignore
@@ -46,7 +46,6 @@
 ssl/ssl_pthread_server
 ssl/ssl_server
 ssl/ssl_server2
-test/benchmark
 test/cpp_dummy_build
 test/cpp_dummy_build.cpp
 test/dlopen